make-pycharm-virtualenv broken after pip drops --egg

pip has dropped the --egg option in pip 10.0.1
{{ https://pip.pypa.io/en/stable/news/#b1-2018-03-31 which has broken our make-pycharm-virtualenv script needed to make development of the client easier on pycharm.}}

Running the script results in the following error:

{{+ VIRTUALENV_VERSION=16.0.0
{{ + which python2.7}}
{{ ++ which python2.7}}
{{ + PY=/usr/local/bin/python2.7}}
{{ + echo 'Using /usr/local/bin/python2.7'}}
{{ Using /usr/local/bin/python2.7}}
{{ +++ dirname ./build-support/virtualenv}}
{{ ++ cd ./build-support}}
{{ ++ pwd}}
{{ + HERE=/Users/rdelvalle/git/aurora/build-support}}
{{ + '[' -f /Users/rdelvalle/git/aurora/build-support/virtualenv-16.0.0/BOOTSTRAPPED ']'}}
{{ + exec /usr/local/bin/python2.7 /Users/rdelvalle/git/aurora/build-support/virtualenv-16.0.0/virtualenv.py --no-download build-support/python/pycharm.venv}}
{{ New python executable in /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python2.7}}
{{ Also creating executable in /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python}}
{{ Installing setuptools, pip, wheel...done.}}Usage:
{{ /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python -m pip install [options] <requirement specifier> [package-index-options] ...}}
{{ /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python -m pip install [options] -r <requirements file> [package-index-options] ...}}
{{ /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python -m pip install [options] [-e] <vcs project url> ...}}
{{ /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python -m pip install [options] [-e] <local project path> ...}}
{{ /Users/rdelvalle/git/aurora/build-support/python/pycharm.venv/bin/python -m pip install [options] <archive url/path> ...}}no such option: --egg}}