git_push_config: drop cargo-culted wt_status pointer

The push config callback does not expect any incoming data
via the void pointer. And if it did, it would certainly not
be a "struct wt_status". This probably got picked up
accidentally in b945901 (push: heed user.signingkey for
signed pushes, 2014-10-22), which copied the template for
the config callback from builtin/commit.c.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/push.c

@@ -473,13 +473,12 @@ static int option_parse_recurse_submodules(const struct option *opt,
 
 static int git_push_config(const char *k, const char *v, void *cb)
 {
-	struct wt_status *s = cb;
 	int status;
 
 	status = git_gpg_config(k, v, NULL);
 	if (status)
 		return status;
-	return git_default_config(k, v, s);
+	return git_default_config(k, v, NULL);
 }
 
 int cmd_push(int argc, const char **argv, const char *prefix)