Reskin: Fix stability bugs introduced by reskin

Bug: 7150348
Bug: 7144206
Bug: 7050303

If PhotoPage is launched/resumed on a completely empty
album (for instance, if Gallery was opened to the Camera
folder and paused, all photos were deleted via the Camera
app, and then Gallery is resumed), bail out of PhotoPage
since it cannot handle this. Also fixes an NPE.

Change-Id: I162ff5ad149c322704c8af7d4705d87ae6c6098a