Debugger: Avoid warnings from debugger when using -client.

Do not parse options if empty (when a file was passed to
the core).

Reviewed-by: Thorbjørn <thorbjorn.lindeijer@nokia.com>

src/plugins/debugger/debuggerplugin.cpp

@@ -2868,6 +2868,9 @@ bool DebuggerPlugin::hasSnapsnots() const
 
 void DebuggerPlugin::remoteCommand(const QStringList &options, const QStringList &)
 {
+    if (options.isEmpty())
+        return;
+
     unsigned enabledEngines = 0;
     QString errorMessage;
     bool success = false;