path: drop git_pathdup() in favor of repo_git_path()

Remove `git_pathdup()` in favor of `repo_git_path()`. The latter does
essentially the same, with the only exception that it does not rely on
`the_repository` but takes the repo as separate parameter.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/tag.c

@@ -667,7 +667,7 @@ int cmd_tag(int argc,
 	if (create_tag_object) {
 		if (force_sign_annotate && !annotate)
 			opt.sign = 1;
-		path = git_pathdup("TAG_EDITMSG");
+		path = repo_git_path(the_repository, "TAG_EDITMSG");
 		create_tag(&object, object_ref, tag, &buf, &opt, &prev, &object,
 			   &trailer_args, path);
 	}