refs: convert reflog_expire parameter to struct object_id

reflog_expire already used struct object_id internally, but it did not
take it as a parameter.  Adjust the parameter (and the callers) to pass
a pointer to struct object_id instead of a pointer to unsigned char.
Remove the temporary inserted earlier as it is no longer required.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/refs.c b/refs.c
index d19fae5..3748528 100644
--- a/refs.c
+++ b/refs.c
@@ -2010,19 +2010,19 @@ int delete_reflog(const char *refname)
 }
 
 int refs_reflog_expire(struct ref_store *refs,
-		       const char *refname, const unsigned char *sha1,
+		       const char *refname, const struct object_id *oid,
 		       unsigned int flags,
 		       reflog_expiry_prepare_fn prepare_fn,
 		       reflog_expiry_should_prune_fn should_prune_fn,
 		       reflog_expiry_cleanup_fn cleanup_fn,
 		       void *policy_cb_data)
 {
-	return refs->be->reflog_expire(refs, refname, sha1, flags,
+	return refs->be->reflog_expire(refs, refname, oid, flags,
 				       prepare_fn, should_prune_fn,
 				       cleanup_fn, policy_cb_data);
 }
 
-int reflog_expire(const char *refname, const unsigned char *sha1,
+int reflog_expire(const char *refname, const struct object_id *oid,
 		  unsigned int flags,
 		  reflog_expiry_prepare_fn prepare_fn,
 		  reflog_expiry_should_prune_fn should_prune_fn,
@@ -2030,7 +2030,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
 		  void *policy_cb_data)
 {
 	return refs_reflog_expire(get_main_ref_store(),
-				  refname, sha1, flags,
+				  refname, oid, flags,
 				  prepare_fn, should_prune_fn,
 				  cleanup_fn, policy_cb_data);
 }