Change RPM repo from Copr 2.3 to CentOS CBS 3.0

Change RPM repo from Copr 2.3 to CentOS CBS 3.0

This both upgrades the version of OpenDaylight that's provided
by the RPM-based install method and changes the repo from which
we serve ODL's RPM.

OpenDaylight Lithium 3.0.0 is now installed via the RPM.

OpenDaylight's RPM is now built and hosted on the CentOS Community
Build System. The CentOS Network Function Virtualization Special
Interest Group (NFV SIG) and the upstream ODL Integration team
made that happen.

Change-Id: I6e269e23d815ac2fef2f2c60fe41ba8d031e2873
Signed-off-by: Daniel Farrell <dfarrell@redhat.com>