Fix crash on screen rotation while setting search engine

Browser was not restoring activity state correctly on screen
rotation. It was overwriting the GeneralPreferenceFragment object
with a new object.

CR-Fixed: 724867

Change-Id: Ifdaf2db9b45429ef1b779224aa12e26ee47d3790
diff --git a/src/com/android/browser/BrowserPreferencesPage.java b/src/com/android/browser/BrowserPreferencesPage.java
index 848c23d..2141490 100644
--- a/src/com/android/browser/BrowserPreferencesPage.java
+++ b/src/com/android/browser/BrowserPreferencesPage.java
@@ -58,6 +58,10 @@
     public void onCreate(Bundle icicle) {
         super.onCreate(icicle);
 
+        if (icicle != null) {
+            return;
+        }
+
         Intent intent = getIntent();
         if (intent != null) {
             String action = intent.getAction();