Merge branch 'kj/refspec-parsing-outside-repository'

"git ls-remote '+refs/tags/*:refs/tags/*' https://..." run outside a repository would dereference a NULL while trying to see if the given refspec is a single-object refspec, which has been corrected. * kj/refspec-parsing-outside-repository: refspec: fix typo in comment remote-curl: fall back to default hash outside repo