TrinityCore/TrinityCore — pull request #6976 by Elron103 (2012-06-29 16:50:34+00:00)
Title: Scripts/Spells: Fix Deathknight ability Death Pact 48743

### Description
The Deathknight ability Death Pact (http://www.wowhead.com/spell=48743) can be used without any undead pet of the caster. This happens because void FilterTarget is not called, if unitList is empty, so there wont be any checks for vadility.

### Fix explanation
Now the checks are done in SpellCastResult CheckCast, so the spell cast will always be aborted there, if no valid target was found.

### Thanks
Special thanks to Kandera.

### Revs
TDB: 46
TC: f0f68f15a86c5ac