[PATCH] autofs4: rename simple_empty_nolock function

Rename the function simple_empty_nolock to __simple_empty in line with kernel
naming conventions.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>