Handle candidate release versions better

Translate the usage of candidate release versions
in requirements into an rpm version + release.

This translation is not perfect but it will work better
than what previously existed (which did not work
at all when there were candiate releases being used
in requirements of various components).

Fixes bug 1304747

Change-Id: I1623112aecc66d6fdc22817704b17c6ff5f3781e
Merge "Handle candidate release versions better"