Running integTests in pygradle-plugin directory modifies python libraries and causes python startup to fail

Nobody has claimed this yet.

Python is installed via brew (python2.7) and python binary is used from /usr/local/Cellar/python/2.7.14_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7

```pygradle-plugin$ python
Python 2.7.14 (default, Jan 6 2018, 12:16:16)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from _struct import *
>>>

drwxr-xr-x 127 admin 4.0K Jan 9 08:39 encodings
drwxr-xr-x 13 admin 416B Jan 9 08:39 config

Now, running tests from inside pygradle-plugin directory:
pygradle-plugin$ ../gradlew integTest

leads to the python libraries being overwritten and the folders are empty.

drwxr-xr-x 2 admin 64B Jan 9 08:43 lib-dynload
drwxr-xr-x 2 admin 64B Jan 9 08:43 encodings
drwxr-xr-x 2 admin 64B Jan 9 08:43 config

python2.7$ python
Python 2.7.14 (default, Jan 6 2018, 12:16:16)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.39.2)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from _struct import *
Traceback (most recent call last):
File "", line 1, in
ImportError: No module named _struct

This is always reproducible by running the integTest from pygradle-plugin directory.

Infact, if you just run PythonPluginIntegrationTest the issue is reproducible, so it does not require the whole set of tests to run.

Run ../gradlew integTest from the pygradle-plugin directory, then isolate PythonPluginIntegrationTest as described. Inspect how that integration test handles the Python libraries; done means the test completes without emptying the Python 2.7 library directories and a subsequent `from _struct import *` succeeds.

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