Added cache invalidation.

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@6357 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/wildfire/spi/PresenceManagerImpl.java

@@ -200,6 +200,10 @@ public class PresenceManagerImpl extends BasicModule implements PresenceManager
             finally {
                 DbConnectionManager.closeConnection(pstmt, con);
             }
+
+            // Remove data from cache.
+            offlinePresenceCache.remove(username);
+            lastActivityCache.remove(username);
         }
     }