Reset the pointer to the Bluetooth GATT service

During error recovery, if the mBluetooth pointer is reset to null,
reset the mBluetoothGatt pointer as well.

Bug: 21756298
Change-Id: I26204ba47dd3c5465bb7de30cfa5dc0f07eee2fd

services/core/java/com/android/server/BluetoothManagerService.java

@@ -1506,6 +1506,7 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
                                 //Unbind
                                 mContext.unbindService(mConnection);
                             }
+                            mBluetoothGatt = null;
                         }
                         SystemClock.sleep(100);
 
@@ -1811,6 +1812,7 @@ class BluetoothManagerService extends IBluetoothManager.Stub {
                 //Unbind
                 mContext.unbindService(mConnection);
             }
+            mBluetoothGatt = null;
         }
 
         mHandler.removeMessages(MESSAGE_BLUETOOTH_STATE_CHANGE);