fs:fuse: Ensure update of fuse inode attributes in shortcircuit

Ensure that in shortcircuit mode the fuse inode attributes always
reflect those of the native filesystem by forcing an attribute copy.

Change-Id: Ie4d322c9b8e0d3b49d195801dab4cc86d8df11e2
Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>