support: PackageListAdapter: really sync mInstalledPackages

synchronized works as expected on final objects

Change-Id: I46897cb9bea214b538841a071bc4976d036f4f31
diff --git a/src/com/bliss/support/preferences/PackageListAdapter.java b/src/com/bliss/support/preferences/PackageListAdapter.java
index 3231305..e057e20 100644
--- a/src/com/bliss/support/preferences/PackageListAdapter.java
+++ b/src/com/bliss/support/preferences/PackageListAdapter.java
@@ -42,7 +42,7 @@
 public class PackageListAdapter extends BaseAdapter implements Runnable {
     private PackageManager mPm;
     private LayoutInflater mInflater;
-    private List<PackageItem> mInstalledPackages = new LinkedList<PackageItem>();
+    private final List<PackageItem> mInstalledPackages = new LinkedList<PackageItem>();
 
     private final Handler mHandler = new Handler() {
         @Override