mm/vmstat.c: remov debug fs entries on failure of file creation and made extfrag_debu...

mm/vmstat.c: remov debug fs entries on failure of file creation and made extfrag_debug_root dentry local

Removed debug fs files and directory on failure.  Since no one using
"extfrag_debug_root" dentry outside of function extfrag_debug_init made it
local to the function.

Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>