Add object-expirer.

Fixes bug 928198.

Change-Id: I0f3bbe323cdb285714d1c80fe7e7b7d9842ece06
diff --git a/files/swift/object-server.conf b/files/swift/object-server.conf
index 06fbffe..2f888a2 100644
--- a/files/swift/object-server.conf
+++ b/files/swift/object-server.conf
@@ -18,3 +18,5 @@
 [object-updater]
 
 [object-auditor]
+
+[object-expirer]