fix GSS on android: we send custom user agent to have info about device, but we need some identifier

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

src/main/java/com/owncloud/android/authentication/AuthenticatorActivity.java

@@ -361,7 +361,7 @@ public class AuthenticatorActivity extends AccountAuthenticatorActivity
 
     private static String getWebLoginUserAgent() {
         return Build.MANUFACTURER.substring(0, 1).toUpperCase(Locale.getDefault()) +
-                Build.MANUFACTURER.substring(1).toLowerCase(Locale.getDefault()) + " " + Build.MODEL;
+            Build.MANUFACTURER.substring(1).toLowerCase(Locale.getDefault()) + " " + Build.MODEL + " (Android)";
     }
 
     @SuppressLint("SetJavaScriptEnabled")