fixed a bug when watch is not connected to a phone, we closed the datastream even its wasn openend

android/ConductorsWatch/app/src/main/java/de/tonifetzer/conductorswatch/network/SensorDataFileStreamer.java

@@ -152,12 +152,15 @@ public class SensorDataFileStreamer implements Runnable{
     }
 
     public void close(){
+        if(mChannelOpenend && mNode != null){
             try {
                 mRunning = false;
                 mOutputStream.close();
                 mOutputStreamOpened = false;
             } catch (IOException e) {
-            e.printStackTrace();
+                //e.printStackTrace();
+                Log.d(TAG, "Closing the outputstream failed!");
+            }
         }
     }
 }