Fix centos6 installation

[hufman]

Centos6 epel has a higher version number than ceph's official repo, but has some bugs. This fixes them.
To get it to work, the Radosgw Apache installation order needed to be changed.

This appears to fix #148.

[hufman]

yum-priorities breaks fc20 installation, because some packages try to install from 'updates' but they don't have enough of the dependencies in the 'ceph' repo, it seems.

[joerocklin]

@hufman There is a similar issue in CentOS 7 (and I presume RHEL 7). I'm working on a bunch of fixes for CentOS 7 which pulls in changes from @tomzo and @cbaker423 as well as your own work. Current WIP is at: https://github.com/joerocklin/ceph-cookbook/tree/centos-7

[tomzo]

@joerocklin Please note that I did not test my changes on CentOS at all. There are lots of general fixes in my fork, but I'd recommend to not merge my entire master branch since it deviated a bit into what my organization needs...

I could create a 'merge-able' branch(es) if you are interested. Otherwise you should really do some cherry-picking. Let me know.

[joerocklin]

@tomzo, thanks for the warning. I'll examine things a little closer before doing a merge request back to the community project.
Edit: If you want to make a merge-able branch, I'd be happy to use that instead.