LU-10855 llog: remove obsolete llog handlers

LU-10855 llog: remove obsolete llog handlers

Remove the obsolete llog RPC handling for cancel, close, and
destroy. Remove llog handling from ldlm_callback_handler(). Remove the
unused client side method llog_client_destroy().

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ieab44f3796971a7d3c65d6044e4c0be4afb4b508
Reviewed-on: https://review.whamcloud.com/32202
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>