PNFS fix EACCESS on commit to DS handling

Commit fabbbee0 "PNFS fix fallback to MDS if got error on
commit to DS" moved the pnfs_set_lo_fail() to unhandled errors
which was not correct and lead to a kernel oops on umount.

Instead, fix the original EACCESS on commit to DS error by
getting the new layout and re-doing the IO.

Fixes: fabbbee0

 ("PNFS fix fallback to MDS if got error on commit to DS")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Cc: stable@vger.kernel.org # v4.12
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>