streaming: make stream_blob_to_fd take struct object_id

Since all of its callers have been updated, modify stream_blob_to_fd to
take a struct object_id.

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

entry.c

@@ -127,7 +127,7 @@ static int streaming_write_entry(const struct cache_entry *ce, char *path,
 	if (fd < 0)
 		return -1;
 
-	result |= stream_blob_to_fd(fd, ce->oid.hash, filter, 1);
+	result |= stream_blob_to_fd(fd, &ce->oid, filter, 1);
 	*fstat_done = fstat_output(fd, state, statbuf);
 	result |= close(fd);