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
Move auth_token config to .conf, key cache directories

auth_token configuration can now be read from the conf files
rather than the paste.ini files.

A key cache directory has been created for each of the 3 API services
under /var/cache/heat

This is the devstack change relating to
Heat Blueprint: keystone-middleware

This is related to this committed change:
https://review.openstack.org/#/c/26351/

Devstack users will find Heat to be broken until this corresponding change
is approved.

Change-Id: If6f77f86a3eeb08a58b516725bd806e39ccedb50
Merge "Move auth_token config to .conf, key cache directories"
Merge "Modify RPM lists for RHEL6"