Don't deregister the host if it wasn't stopped.

remoting/webapp/host_controller.js

Index: remoting/webapp/host_controller.js
diff --git a/remoting/webapp/host_controller.js b/remoting/webapp/host_controller.js
index 2236c6379126f215d5ccb97bc883a85a55dd00ca..5f45dae161d99727aa4cec906c57b0d0f414d23d 100644
--- a/remoting/webapp/host_controller.js
+++ b/remoting/webapp/host_controller.js
@@ -242,7 +242,8 @@ remoting.HostController.prototype.stop = function(callback) {
 
   /** @param {remoting.HostController.AsyncResult} result */
   function onStopped(result) {
-    if (that.localHost && that.localHost.hostId) {
+    if (result == remoting.HostController.AsyncResult.OK &&
+        that.localHost && that.localHost.hostId) {
       remoting.HostList.unregisterHostById(that.localHost.hostId);
     }
     callback(result);