fix getItemId crash on empty cursors

getItem() is usually not called from within getItemId(). Turns out this
is not a great combo, because getItemId() must handle any input, but
getItem() doesn't. Switch to using Cursor.moveToPosition() directly so zero-
sized cursors trigger the default CursorAdapter.getItemId() codepath.

Bug: 9167831
Change-Id: Ie46572eea69b8dec7e4aba3d76d3c841c4f98c46
1 file changed