Merge pull request #15 from hannesa2/FixNPE

Fixed NPE

Author: hannesa2

org.eclipse.paho.android.service/src/main/java/org/eclipse/paho/android/service/MqttConnection.java

@@ -176,11 +176,10 @@ public void connect(MqttConnectOptions options, String invocationContext, String
 
         if (options != null) {
             cleanSession = options.isCleanSession();
-        }
-
-        if (connectOptions.isCleanSession()) { // if it's a clean session,
-            // discard old data
-            service.messageStore.clearArrivedMessages(clientHandle);
+            if (options.isCleanSession()) { // if it's a clean session,
+                // discard old data
+                service.messageStore.clearArrivedMessages(clientHandle);
+            }
         }
 
         service.traceDebug(TAG, "Connecting {" + serverURI + "} as {" + clientId + "}");