Add missing return statement on LBA range locking failure. Fixes github issue #1531 Signed-off-by: Maciej Szwed <maciej.szwed@intel.com> Change-Id: I5506f34acd51714b9947b9692d0d5d9793144adc Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3737 Community-CI: Mellanox Build Bot Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com> Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>