Merge branch 'jc/push-cert' into maint

"git push --signed" gave an incorrectly worded error message when
the other side did not support the capability.

* jc/push-cert:
  transport-helper: fix typo in error message when --signed is not supported

transport-helper.c

@@ -862,7 +862,7 @@ static int push_refs_with_export(struct transport *transport,
 			die("helper %s does not support dry-run", data->name);
 	} else if (flags & TRANSPORT_PUSH_CERT) {
 		if (set_helper_option(transport, TRANS_OPT_PUSH_CERT, "true") != 0)
-			die("helper %s does not support dry-run", data->name);
+			die("helper %s does not support --signed", data->name);
 	}
 
 	if (flags & TRANSPORT_PUSH_FORCE) {