Fix stale data due to stopped loader.

Bug 33185424

When stopping an CursorLoader while data is being loaded,
the load task will be canceled. This CL marks the data as
changed if the cancel is called while the loader is stopped.

Test: I63b48210a25be72d13a2a6182eb1757cbe6a1949
Change-Id: Ibf9c5facdcc5160f6ed146c5fdd063549ac2a7a8