Fix NPE when closing a CM connection. JM-881

git-svn-id: http://svn.igniterealtime.org/svn/repos/wildfire/trunk@5849 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/wildfire/SessionManager.java

@@ -1535,6 +1535,7 @@ public class SessionManager extends BasicModule {
             // Remove all the hostnames that were registered for this server session
             String domain = session.getAddress().getDomain();
             List<ConnectionMultiplexerSession> sessions = connnectionManagerSessions.get(domain);
+            if (sessions != null) {
                 sessions.remove(session);
                 if (sessions.isEmpty()) {
                     connnectionManagerSessions.remove(domain);
@@ -1544,6 +1545,7 @@ public class SessionManager extends BasicModule {
                 }
             }
         }
+    }
 
     public void initialize(XMPPServer server) {
         super.initialize(server);