tmpfs: handle MPOL_LOCAL mount option properly

commit 71fe804b6d5 (mempolicy: use struct mempolicy pointer in
shmem_sb_info) added mpol=local mount option.  but its feature is broken
since it was born.  because such code always return 1 (i.e.  mount
failure).

This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 10db44f..fb71790 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2214,6 +2214,7 @@
 		if (nodelist)
 			goto out;
 		mode = MPOL_PREFERRED;
+		err = 0;
 		break;
 	case MPOL_DEFAULT:
 		/*