Remove core script for rogue trainers which was overriding db conditions...

... and allowing non rogues to access trainer

Further to the sai i writ a few months ago as replacement to the core script used by rogue trainers, the only reason rogue trainers had this script was to add the elegant letter, no other class trainers use such script, the rest of the options are dealt with in same way as other trainers, gossip options, conditions, etc.

This has had a couple of months of testing and have heard no problems since i first implemented sai and of course trainers behave as they should ie not allowing non rogues to access trainer options

SAI here for the elegant letter https://github.com/TrinityCore/TrinityCore/issues/9952#issuecomment-27155960, other options dealt with by gossip options, conditions in same way as other class trainers,