Merge branch 'jc/cocci-cleanup'

Remove a coccinelle rule that is no longer relevant.

* jc/cocci-cleanup:
  cocci: retire is_null_sha1() rule

contrib/coccinelle/object_id.cocci

@@ -1,15 +1,3 @@
-@@
-struct object_id OID;
-@@
-- is_null_sha1(OID.hash)
-+ is_null_oid(&OID)
-
-@@
-struct object_id *OIDPTR;
-@@
-- is_null_sha1(OIDPTR->hash)
-+ is_null_oid(OIDPTR)
-
 @@
 struct object_id OID;
 @@