Remove get_object_hash.

Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object.  This provides no
functional change, as it is essentially a macro substitution.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 9985949..7e074aa 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -282,7 +282,7 @@
 			exclude = get_merge_bases(a, b);
 			while (exclude) {
 				struct commit *commit = pop_commit(&exclude);
-				show_rev(REVERSED, get_object_hash(commit->object), NULL);
+				show_rev(REVERSED, commit->object.oid.hash, NULL);
 			}
 		}
 		*dotdot = '.';
@@ -319,7 +319,7 @@
 	commit = lookup_commit_reference(sha1);
 	for (parents = commit->parents; parents; parents = parents->next)
 		show_rev(parents_only ? NORMAL : REVERSED,
-				get_object_hash(parents->item->object), arg);
+				parents->item->object.oid.hash, arg);
 
 	*dotdot = '^';
 	return 1;