When "git describe" returns an "rc" tag (eg "2.2.0rc1"), insert the RC
number into the RPM's "Release" field.
Add comments with some git-describe values and NVRs.
Prior to this change, if we built an RPM from a tagged commit, the RPM
would have a release value of "0".
This causes some problems with RPM version comparisons when comparing
version numbers with "rc" tags/packages, which should also have a
less-than-one Release value.
Prior to this change, if there was a stray tag in the repository that
did not start with a "v", the Makefile would still try to use that tag
as a version tag when constructing the RPMs.
Only use the tags that start with "v", in this case.
Prior to this change, all RPMs would have a Version field that started
with "v", for example "ceph-ansible-v2.0.0-163.g2c98b1d.el7"
Strip the "v" out in these cases, so that the version is simply a
number.
"make rpm" will build a ceph-ansible RPM and place it in the current
working directory.
This will allow us to run this command in Jenkins for every branch.