Fix function name in error msg

Modules/fcntlmodule.c

@@ -327,7 +327,7 @@ fcntl_lockf(PyObject *self, PyObject *args)
 			l.l_type = F_WRLCK;
 		else {
 			PyErr_SetString(PyExc_ValueError,
-					"unrecognized flock argument");
+					"unrecognized lockf argument");
 			return NULL;
 		}
 		l.l_start = l.l_len = 0;