Merge branch 'rs/free-and-null'

Code cleanup.

* rs/free-and-null:
  coccinelle: polish FREE_AND_NULL rules

contrib/coccinelle/free.cocci

@@ -10,17 +10,9 @@ expression E;
 - if (!E)
   free(E);
 
-@@
-type T;
-T *ptr;
-@@
-- free(ptr);
-- ptr = NULL;
-+ FREE_AND_NULL(ptr);
-
 @@
 expression E;
 @@
 - free(E);
-- E = NULL;
 + FREE_AND_NULL(E);
+- E = NULL;