COMP: CTestCustom: Add warning exceptions to avoid false positive

This commit prevents the following warnings from being reported as error
on CDash:

C:\D\S4R\python-install\Lib\distutils\dist.py:267: UserWarning: Unknown distribution option: 'test_suite'
C:\D\S4R\python-install\Lib\distutils\dist.py:267: UserWarning: Unknown distribution option: 'tests_require'
C:\D\S4R\python-install\Lib\distutils\dist.py:267: UserWarning: Unknown distribution option: 'install_requires'
C:\D\S4R\python-install\lib\site-packages\setuptools-35.0.1.post20170425-py2.7.egg\setuptools\dist.py:334: UserWarning: Normalizing '0.30.0.a0' to '0.30.0a0'

Reported-by: Andras Lasso <lasso@queensu.ca>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@25965 3bd1e089-480b-0410-8dfb-8563597acbee