dm thin: fix dangling bio in process_deferred_bios error path

commit fe76cd88e654124d1431bb662a0fc6e99ca811a5 upstream.

If unable to ensure_next_mapping() we must add the current bio, which
was removed from the @bios list via bio_list_pop, back to the
deferred_bios list before all the remaining @bios.

Change-Id: If1c8ec4babf4a8b2bc020b85c6452d93cf6bae06
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux 3.4.90

Change-Id: I18f2be7ce66b3d505b700e01dc60c85d86edfd89
Update defconfig for 3.4.90

Change-Id: I1f0ae6f9a737d4cba77295f4587c46b0ede7fab5