Prevent crash in VNC plugin when you connect to a server that's not available.

Patch by Patch by Wouter Van Meir <wouter.vanmeir pandora.be>, thanks.

svn path=/trunk/KDE/kdenetwork/krdc/; revision=1152685

vnc/vncclientthread.cpp

@@ -330,6 +330,8 @@ void VncClientThread::run()
 
         if (rfbInitClient(cl, 0, 0))
             break;
+        else
+            cl = 0;
 
         locker.relock();
         if (m_passwordError)