Fix pip in centos6

puppet looks for pip-python (rather than pip) when osfamily is
redhat. Somehow this wasn't causing a problem before (presumably
pip-python package was left behind but something has changed
upstream) and now we need to create a symlink for rhel6 as well.

Change-Id: I1f11aa7f6b33aa846e10715dd1653bb43e1c9d7e
Merge "Fix pip in centos6"