Modify RPM lists for RHEL6

Modifications to the RPM list to make devstack work on RHEL6.  Makes
various packages only install on Fedora distros; generally letting pip
install the missing dependencies on RHEL.

Additionally the Qpid package name is different in RHEL6 to Fedora.
Also a small re-write of the config file is required to avoid
authenication issues.

Change-Id: If497099d27aa9cd80e1c1cee1aff2ed6b076d309
Merge "Modify RPM lists for RHEL6"