Update incorrect comment about nova-network status

The network manifest contained a comment that said that nova-network
was no longer receiving any patches.  That's not actually the case, so
replace the comment with a new description that describes the current
state.

The openstack-dev post that officially unfroze nova-network is here:

http://lists.openstack.org/pipermail/openstack-dev/2014-January/025824.html

Change-Id: Ifbe2ec0b9e7971bb85f84b4cb3c014eeb4e6efde
Make Modulefile summary and description consistent

Improve consistency of Modulefile across puppet modules for OpenStack.

Change-Id: I60d813013400a7773b4aec2225d0455071b12c2a
Fixes Facts string comparisons in CentOS 7

- CentOS Project has adopted a new rule for versioning numbers. The major number
  matches the RHEL major number, but the minor number is generated from the
  release date. For example, CentOS 7.1407.
- Adds Support for Scientific Linux.

Change-Id: I8ffb63ba3409c7595a0f13b5ec93c87b1d534d02
Closes-Bug: 1338777
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>