Fix "connected" message missing in some cases

Once a disconnect message was printed once it would not print a connect
message for the same session again since a timer id wasn't reset.

No unit test was possible since the mock-socket has certain
incompatibilities/limitations that make it impossible to distinguish
different sockets. An upgrade of that module introduced different
problems documented in CLI issue #75

Change-Id: I187ccb4ac4e84009dc8dc144c66eccf52e4d06a5

src/services/DebugServer.js

@@ -94,6 +94,7 @@ module.exports = class DebugServer {
 
   _onDisconnect(connection) {
     this._printStateTimer = setTimeout(() => {
+      this._printStateTimer = -1;
       this._printClientState(connection.device, STATE_DISCONNECTED);
       if (this._onEvaluationCompleted) {
         this._onEvaluationCompleted();