On RHEL-based systems pip and yum share the same installation
directory for virtualenv. If yum pulls in the python-virtualenv
package (e.g. due to a dependency) it will clobber what pip has
already installed. The file tools/fixup_stuff.sh tries to ensure that
the proper virtualenv package is installed via pip. If virtualenv has
already been installed via pip, then clobbered by yum, pip skips the
install since it appears as if virtualenv is already installed and at
the correct version.
The reinstall of virtualenv must use the --force-reinstall argument to
pip to fix up the damage done by yum.
Change-Id: Ib0edf6c4ee8a510e9d671213de35d787f56acfed
Closes-Bug: #1599863
df6c1ffbe1