Fix browser crash.

I'm looking at you, Derek...

Bug: 2947089
Change-Id: I7a51c7007f46b9e0a2ec1d8ca6d66b879c565aca
diff --git a/src/com/android/browser/BrowserActivity.java b/src/com/android/browser/BrowserActivity.java
index 5a1cf55..2ef5ee6 100644
--- a/src/com/android/browser/BrowserActivity.java
+++ b/src/com/android/browser/BrowserActivity.java
@@ -991,8 +991,6 @@
         mTabControl.destroy();
         WebIconDatabase.getInstance().close();
 
-        unregisterReceiver(mPackageInstallationReceiver);
-
         // Stop watching the default geolocation permissions
         mSystemAllowGeolocationOrigins.stop();
         mSystemAllowGeolocationOrigins = null;
@@ -4337,8 +4335,6 @@
     private IntentFilter mNetworkStateChangedFilter;
     private BroadcastReceiver mNetworkStateIntentReceiver;
 
-    private BroadcastReceiver mPackageInstallationReceiver;
-
     private SystemAllowGeolocationOrigins mSystemAllowGeolocationOrigins;
 
     // activity requestCode