Workaround for Android network bug

Android 6.0 Huawei Che2-L11

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

@@ -264,6 +264,10 @@ public class ConnectionHelper {
                     Log.i("isMetered: underlying is unmetered");
                     return false;
                 }
+            } else {
+                // Workaround: active network = VPN, active network info = WiFi
+                if (network.equals(active) && !cm.isActiveNetworkMetered())
+                    return false;
             }
         }