If we are based on a git tag with a name (such as 'upstream/2.10.2'),
remove everything up to the slash.
While we're at it, remove a leading '1%' that gets into the version
string as part of the version tag (a Debian version with an epoch: '1:'
is converted to '1%').
Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>