android: Delete PRIVATE_API bridge mode enum, since it was removed in 4.0.0
diff --git a/src/android/exec.js b/src/android/exec.js
index b9112d7..fa8b41b 100644
--- a/src/android/exec.js
+++ b/src/android/exec.js
@@ -51,11 +51,7 @@
         // For the ONLINE_EVENT to be viable, it would need to intercept all event
         // listeners (both through addEventListener and window.ononline) as well
         // as set the navigator property itself.
-        ONLINE_EVENT: 2,
-        // Uses reflection to access private APIs of the WebView that can send JS
-        // to be executed.
-        // Requires Android 3.2.4 or above.
-        PRIVATE_API: 3
+        ONLINE_EVENT: 2
     },
     jsToNativeBridgeMode,  // Set lazily.
     nativeToJsBridgeMode = nativeToJsModes.ONLINE_EVENT,