Added network bug workaround

app/src/main/java/eu/faircode/email/ConnectionHelper.java

@@ -187,8 +187,14 @@ public class ConnectionHelper {
         Network active = cm.getActiveNetwork();
         if (active == null) {
             Log.i("isMetered: no active network");
+            // Workaround bug in some Android versions
+            NetworkInfo ani = cm.getActiveNetworkInfo();
+            if (ani == null || !ani.isConnected()) {
+                Log.i("isMetered: no active network=" + (ani == null ? null : ani.isConnected()));
                 return null;
             }
+            return cm.isActiveNetworkMetered();
+        }
 
         // onLost [... state: DISCONNECTED/DISCONNECTED ... available: true]
         NetworkInfo ani = cm.getNetworkInfo(active);