LU-4214 target: LWP failover should create new export

LU-4214 target: LWP failover should create new export

Upon reconnection from new NID LWP client need to create new
export and destroy old one like that is done for MDS connection

Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Change-Id: Id21a742a978f629e2324bc568a1a50c2922fe3cc
Reviewed-on: http://review.whamcloud.com/8465
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Johann Lombardi <johann.lombardi@intel.com>