cache: convert struct cache_entry to use struct object_id

Convert struct cache_entry to use struct object_id by applying the
following semantic patch and the object_id transforms from contrib, plus
the actual change to the struct:

@@
struct cache_entry E1;
@@
- E1.sha1
+ E1.oid.hash

@@
struct cache_entry *E1;
@@
- E1->sha1
+ E1->oid.hash

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rm.c

@@ -199,7 +199,7 @@ static int check_local_mod(unsigned char *head, int index_only)
 		if (no_head
 		     || get_tree_entry(head, name, sha1, &mode)
 		     || ce->ce_mode != create_ce_mode(mode)
-		     || hashcmp(ce->sha1, sha1))
+		     || hashcmp(ce->oid.hash, sha1))
 			staged_changes = 1;
 
 		/*