LU-5957 mdt: Update MDT flags after layout swap

LU-5957 mdt: Update MDT flags after layout swap

Swap MOF_LOV_CREATED flags between MDT objects after a layout swap to
guarantee that layout will be re-created on next write if its LOV has
been deleted.

Signed-off-by: Henri Doreau <henri.doreau@cea.fr>
Change-Id: I3d0497d8be2a7335c1fb43e10af2b222243e6a81
Reviewed-on: http://review.whamcloud.com/12877
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: frank zago <fzago@cray.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>