Fetch Disassembly fails if the source file path has blanks

It is relatively straightforward -- the path after "-f" is not quoted, so if there is a blank in the file path, it fails. Solution: quote the path. I tried to manually fire the data disassemble command with a quoted path, and it works well.

**Please complete the following information:**
* OS: Linux 18.04
* gdbgui version (`gdbgui -v`): 0.13.1.1
* gdb version (`gdb -v`): GNU gdb (Ubuntu 8.2-0ubuntu1~18.04) 8.2
* browser [e.g. chrome, safari]: chrome 72
* python packages (`pip freeze`):

absl-py==0.5.0
ailment==7.8.9.26
alembic==0.8.8
altgraph==0.16.1
ana==0.5
androguard==3.0.1
angr==7.8.9.26
aniso8601==4.0.1
archinfo==7.8.9.26
argh==0.26.2
asn1crypto==0.24.0
astor==0.7.1
astroid==1.6.5
attrs==18.2.0
Automat==0.7.0
backports-abc==0.5
backports.functools-lru-cache==1.5
backports.shutil-get-terminal-size==1.0.0
backports.weakref==1.0.post1
bcrypt==3.1.5
beautifulsoup4==4.5.3
bitstring==3.1.5
bleach==2.1.4
blessed==1.15.0
boto==2.49.0
boto3==1.9.34
botocore==1.12.34
bottle==0.12.13
bz2file==0.98
bzr==2.8.0.dev1
cachetools==2.1.0
capstone==4.0.0rc1
certifi==2018.8.24
cffi==1.7.0
chardet==2.3.0
claripy==7.8.9.26
cle==7.8.9.26
click==6.6
colorama==0.3.7
configobj==5.0.6
configparser==3.5.0
constantly==15.1.0
cooldict==1.3
cryptography==2.3.1
Cuckoo==2.0.6.2
cycler==0.10.0
decorator==4.3.0
defusedxml==0.5.0
dis3==0.1.2
Django==1.8.4
django-extensions==1.6.7
dnspython==1.16.0
docutils==0.14
dpkt==1.9.1
dpkt-fix==1.7
dumbnet==1.12
ecdsa==0.13
egghatch==0.2.3
elasticsearch==5.3.0
entrypoints==0.2.3
enum34==1.1.6
eventlet==0.24.1
filelock==3.0.10
Flask==0.12.2
Flask-Compress==1.4.0
Flask-Cors==3.0.7
Flask-Login==0.4.1
Flask-RESTful==0.3.6
Flask-Session==0.3.1
Flask-SocketIO==2.9.6
Flask-SQLAlchemy==2.1
frida==12.2.14
frida-tools==1.2.2
funcsigs==1.0.2
functools32==3.2.3.post2
future==0.16.0
futures==3.2.0
gast==0.2.0
gdbgui==0.13.1.1
gensim==3.6.0
gevent==1.3.7
gitdb2==2.0.4
GitPython==2.1.9
greenlet==0.4.15
grpcio==1.15.0
h5py==2.8.0
h5pyViewer==0.0.1.6
html5lib==1.0.1
httplib2==0.9.2
HTTPReplay==0.2.4
hyperlink==18.0.0
idalink==0.10
idna==2.7
incremental==17.5.0
intervaltree==3.0.2
ipaddr==2.2.0
ipaddress==1.0.22
ipykernel==4.10.0
ipython==5.8.0
ipython-genutils==0.2.0
ipywidgets==7.4.2
isort==4.3.4
itsdangerous==0.24
jieba==0.39
Jinja2==2.9.6
jmespath==0.9.3
jsbeautifier==1.6.2
jsonschema==2.6.0
jupyter==1.0.0
jupyter-client==5.2.3
jupyter-console==5.2.0
jupyter-core==4.4.0
Keras==2.2.2
Keras-Applications==1.0.4
Keras-Preprocessing==1.0.2
keyring==10.6.0
keyrings.alt==3.0
keystone-engine==0.9.1.post3
kiwisolver==1.0.1
launchpadlib==1.10.6
lazr.restfulclient==0.13.5
lazr.uri==1.0.3
lazy-object-proxy==1.3.1
libvirt-python==4.0.0
lxml==4.2.1
macholib==1.11
Mako==1.0.7
Markdown==3.0
MarkupSafe==1.0
matplotlib==2.2.3
mccabe==0.6.1
mistune==0.8.3
mock==2.0.0
monotonic==1.5
mpmath==1.0.0
mulpyplexer==0.8
mysql-connector-python==2.1.6
mysql-utilities==1.6.4
nbconvert==5.4.0
nbformat==4.4.0
networkx==2.1
nose==1.3.7
notebook==5.7.0
numpy==1.15.2
oauth==1.0.1
olefile==0.43
oletools==0.51
packaging==18.0
pandas==0.23.4
pandocfilters==1.4.2
paramiko==2.4.2
pathlib2==2.3.2
pathtools==0.1.2
pbr==4.2.0
peepdf==0.4.2
pefile==2018.8.8
pefile2==1.2.11
pexpect==4.6.0
pickleshare==0.7.5
Pillow==3.2.0
pluggy==0.8.0
plumbum==1.6.7
progressbar==2.3
prometheus-client==0.3.1
prompt-toolkit==1.0.15
protobuf==3.6.1
psutil==5.4.8
ptyprocess==0.6.0
pwn==1.0
pwntools==3.12.1
py==1.7.0
pyasn1==0.4.4
pyasn1-modules==0.2.2
PyAutoGUI==0.9.38
pycairo==1.16.2
pycparser==2.18
pycrypto==2.6.1
pyDes==2.0.1
pyelftools==0.24
pygame==1.9.4
pygdbmi==0.9.0.0
pyglet==1.3.2
Pygments==2.2.0
pygobject==3.26.1
pyguacamole==0.6
PyHamcrest==1.9.0
PyInstaller==3.4
pylint==1.9.3
pymisp==2.4.54
pymongo==3.0.3
PyMsgBox==1.0.6
PyNaCl==1.3.0
pyOpenSSL==18.0.0
pypandoc==1.4
pyparsing==2.2.1
PyPDF2==1.26.0
PyScreeze==0.1.18
pyserial==3.4
pysigset==0.3.2
PySocks==1.6.8
python-dateutil==2.4.2
python-editor==1.0.3
python-engineio==2.3.2
python-magic==0.4.12
python-socketio==2.0.0
pythonaes==1.0
PyTweening==1.0.3
pytz==2018.5
pyvex==7.8.9.26
PyWavelets==1.0.1
pyxdg==0.25
PyYAML==3.13
pyzmq==17.1.2
qtconsole==4.4.1
qtfaststart==1.8
requests==2.13.0
requests-unixsocket==0.1.5
roach==0.1.2
rope==0.11.0
ROPGadget==5.4
rpyc==3.3.0
s3transfer==0.1.13
scandir==1.9.0
scapy==2.3.2
schedule==0.5.0
scikit-learn==0.20.0
scipy==1.1.0
scour==0.36
scruffington==0.3.7
SecretStorage==2.3.1
Send2Trash==1.5.0
service-identity==18.1.0
SFlock==0.3.6
simplegeneric==0.8.1
simplejson==3.13.2
singledispatch==3.4.0.3
six==1.11.0
sklearn==0.0
smart-open==1.7.1
smmap2==2.0.4
sortedcontainers==1.5.10
spark-parser==1.8.7
SQLAlchemy==1.0.8
style==1.1.0
subprocess32==3.5.2
-e git://github.com/sympy/sympy.git@990f254ed04d35ae51ef27443ef2fd7349fad004#egg=sympy
tensorboard==1.10.0
tensorflow==1.10.1
termcolor==1.1.0
terminado==0.8.1
testpath==0.4.1
tlslite-ng==0.6.0
toml==0.10.0
torch==0.4.1
torch-vision==0.1.6.dev0
tornado==5.1.1
tox==3.6.0
tqdm==4.26.0
traitlets==4.3.2
Twisted==18.7.0
uncompyle6==3.2.4
unicorn==1.0.1
update==0.0.1
urllib3==1.23
urwid==2.0.1
vboxapi==1.0
virtualenv==16.1.0
voltron==0.1.7
wadllib==1.3.2
wakeonlan==0.2.2
watchdog==0.9.0
wcwidth==0.1.7
webencodings==0.5.1
Werkzeug==0.14.1
widgetsnbextension==3.4.2
wisdom==0.1.0
wrapt==1.10.11
wxPython==4.0.4
xdis==3.8.8
xprint==1.1.12
yara-python==3.6.3
z3-solver==4.5.1.0.post2
zope.interface==4.5.0

Reproduce Fetch Disassembly with a source file path containing blanks, then inspect how the data disassemble command builds the argument after "-f". Done means the command succeeds for paths with spaces and continues to fetch the disassembly; the issue names no file or test to run.

Written by the indexing model from the issue text.