Napalm discards configuration

###Description
If a user is connected to a Junos router using CLI, enters edit mode, makes a change but does not commit (stays in edit mode) - then another user using the Napalm net.load_config function tries to make another different config change, the "LockError" message is received ok but Napalm still discards the uncommitted CLI change.

Versions Report

xxxxxx@xxxxx:~$ sudo salt --versions-report
Salt Version:
Salt: 2016.11.1

Dependency Versions:
cffi: 1.9.1
cherrypy: 3.2.2
dateutil: 1.5
gitdb: 0.5.4
gitpython: 0.3.2 RC1
ioflo: Not Installed
Jinja2: 2.9.5
libgit2: Not Installed
libnacl: Not Installed
M2Crypto: Not Installed
Mako: 0.9.1
msgpack-pure: Not Installed
msgpack-python: 0.4.6
mysql-python: 1.2.3
pycparser: 2.17
pycrypto: 2.6.1
pygit2: Not Installed
Python: 2.7.6 (default, Oct 26 2016, 20:30:19)
python-gnupg: Not Installed
PyYAML: 3.12
PyZMQ: 14.0.1
RAET: Not Installed
smmap: 0.8.2
timelib: Not Installed
Tornado: 4.2.1
ZMQ: 4.0.5

System Versions:
dist: Ubuntu 14.04 trusty
machine: x86_64
release: 3.16.0-30-generic
system: Linux
version: Ubuntu 14.04 trusty

Start with the Napalm net.load_config entry point and reproduce the Junos scenario with one user holding an uncommitted CLI edit while another submits a different change. Trace the LockError handling and verify that a failed load leaves the existing uncommitted configuration intact.