rpmbuild: dist-git-client: strip trailing / from clone url
    
    Clone "url" in .git/config can have trailing slash, like '..foo.git/'.
    This would be a valid URL, but without stripping the trailing slash(es)
    we would mistakenly calculate the namespace[] array (off-by-one after
    the url.split("/"))
    
    Merges: #2350