guess: handle "VX.Y.Z" Git tags
guess: handle "VX.Y.Z" Git tags

NFS-Ganesha uses this tag style

https://github.com/openstack-packages/rdopkg/issues/96

Change-Id: I65d7d3340539410ee59bb3d36a80dc3199df4ebc

openstack-packages/rdopkg,redhat-openstack/rdopkg,openstack-packages/rdopkg,redhat-openstack/rdopkg