Bug fix for Nav screen back button

Fixes a bug which required the back button to be clicked 2x
in order to go back.  Now, back is initiated on first click.

Change-Id: Ibdfb20c93a045af3e9cb7f53887634a000dab80f
diff --git a/src/com/android/browser/PhoneUi.java b/src/com/android/browser/PhoneUi.java
index 477f006..17de464 100644
--- a/src/com/android/browser/PhoneUi.java
+++ b/src/com/android/browser/PhoneUi.java
@@ -336,6 +336,7 @@
         });
         set1.playSequentially(inanim, blend1);
         set1.start();
+        mUiController.setBlockEvents(false);
     }
 
     private void finishAnimationIn() {