[9962] Modify way 4x damage bonus claculated for spell 1120 and ranks.

* Now apply 4x bonus dependent from target health in time spell cast,
  not from current health in tick.
* 4x bonus applied to own spell damage value, not to total taken damage.

src/game/SpellAuras.cpp

@@ -4888,6 +4888,16 @@ void Aura::HandlePeriodicDamage(bool apply, bool Real)
                 }
                 break;
             }
+            case SPELLFAMILY_WARLOCK:
+            {
+                // Drain Soul
+                if (m_spellProto->SpellFamilyFlags & UI64LIT(0x0000000000004000))
+                {
+                    if (m_target->GetHealth() * 100 / m_target->GetMaxHealth() <= 25)
+                        m_modifier.m_amount *= 4;
+                }
+                break;
+            }
             case SPELLFAMILY_DRUID:
             {
                 // Rake

src/game/Unit.cpp

@@ -9125,15 +9125,7 @@ uint32 Unit::SpellDamageBonusDone(Unit *pVictim, SpellEntry const *spellProto, u
             break;
         }
         case SPELLFAMILY_WARLOCK:
-        {
-            // Drain Soul
-            if (spellProto->SpellFamilyFlags & UI64LIT(0x0000000000004000))
-            {
-                if (pVictim->GetHealth() * 100 / pVictim->GetMaxHealth() <= 25)
-                    DoneTotalMod *= 4;
-            }
             break;
-        }
         case SPELLFAMILY_PRIEST:
         {
             // Glyph of Smite

src/shared/revision_nr.h

@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "9961"
+ #define REVISION_NR "9962"
 #endif // __REVISION_NR_H__