Code review comment for lp:~laurynas-biveinis/percona-server/merge-5.6.17

Not sure how you would like to address comments related to lock_rec_other_trx_holds_expl(). I see 3 options on the order of descending efficiency: 1) implement my suggestions 2) revert to the previous implementation 3) leave as is. I'm fine with all of them, so setting to Approved.