ss: return -1 if an unrecognized option was given

When getopt_long encounters an option which has not been registered, it
returns '?'. React upon that and call usage() instead of help() so ss
returns with a non-zero exit status.

Signed-off-by: Phil Sutter <phil@nwl.cc>

misc/ss.c

@@ -3770,8 +3770,8 @@ int main(int argc, char *argv[])
 				exit(1);
 			break;
 		case 'h':
-		case '?':
 			help();
+		case '?':
 		default:
 			usage();
 		}