get-template-library: fix --pull-request for repository with a master branch when using tag rather than HEAD
get-template-library: fix --pull-request for repository with a master branch
when using tag rather than HEAD

quattor/release,brunocanning/release,jrha/release,jrha/release,jrha/release,jouvin/release,stdweird/release,quattor/release,wdpypere/release,wdpypere/release,quattor/release,jouvin/release,brunocanning/release,wdpypere/release,stdweird/release,brunocanning/release,jouvin/release