Merge branch 'jc/cocci-free-updates' into jch

Updates to Coccinelle semantic patches to correctly handle the
'FREE_AND_NULL()' macro and avoid generating broken transformations
for negated pointer checks.

* jc/cocci-free-updates:
  cocci: FREE_AND_NULL(E) is safe to call on NULL
  cocci: remove risky "if (!E) free(E)" conversion

Author: gitster

tools/coccinelle/free.cocci

@@ -6,16 +6,8 @@ expression E;
   free(E);
 |
   commit_list_free(E);
-)
-
-@@
-expression E;
-@@
-- if (!E)
-(
-  free(E);
 |
-  commit_list_free(E);
+  FREE_AND_NULL(E);
 )
 
 @@