Clear the camera instance before switching.

bug:12452510
Change-Id: If8bbd4d8a15ce2ba65659c02063da3a2960142ce
diff --git a/src/com/android/camera/PhotoModule.java b/src/com/android/camera/PhotoModule.java
index 26c4c03..339de43 100644
--- a/src/com/android/camera/PhotoModule.java
+++ b/src/com/android/camera/PhotoModule.java
@@ -410,6 +410,7 @@
         SettingsManager settingsManager = mActivity.getSettingsManager();
 
         Log.v(TAG, "Start to switch camera. id=" + mPendingSwitchCameraId);
+        closeCamera();
         mCameraId = mPendingSwitchCameraId;
         mPendingSwitchCameraId = -1;
         settingsManager.set(SettingsManager.SETTING_CAMERA_ID, "" + mCameraId);