Don't wipe PST partition if OEM unlock is enabled

This will be wiped by the recovery system and the OEM
unlock bit will be retained.

Bug: 16631974
Change-Id: I65522dd93c8465ff7f7ecbcef404bff6e9c864d6

src/com/android/settings/MasterClearConfirm.java

@@ -65,7 +65,10 @@ public class MasterClearConfirm extends Fragment {
                     getActivity().getSystemService(Context.PERSISTENT_DATA_BLOCK_SERVICE);
 
             if (pdbManager != null) {
-                pdbManager.wipe();
+                // if OEM unlock is enabled, this will be wiped during FR process.
+                if (!pdbManager.getOemUnlockEnabled()) {
+                    pdbManager.wipe();
+                }
             }
 
             if (mEraseSdCard) {