When issuing discard request over 512KiB OCF would trim this request and
overwrite req->core_line_count which would then cause this request to be
freed from wrong mpool.
This is fixed now by saving core_line_count that was set when allocating
this request that is never overwritten. This alloc_core_line_count is
then used to free the request from correct mpool.
Signed-off-by: Jan Musial <jan.musial@intel.com>
9c070c1d25