Fix a mem leak in OutdoorPvPMgr's destructor.

log:

==12080== 1,680 (168 direct, 1,512 indirect) bytes in 1 blocks are definitely lost in loss record 106 of 253
==12080==    at 0x4C2626C: operator new(unsigned long) (vg_replace_malloc.c:230)
==12080==    by 0xA63AE9: OutdoorPvPMgr::InitOutdoorPvP() (OutdoorPvPMgr.cpp:51)
==12080==    by 0xC01BDA: World::SetInitialWorldSettings() (World.cpp:1650)
==12080==    by 0x808EF6: Master::Run() (Master.cpp:235)
==12080==    by 0x8083B5: main (Main.cpp:154)

--HG--
branch : trunk

src/game/OutdoorPvPMgr.cpp

@@ -42,6 +42,7 @@ OutdoorPvPMgr::~OutdoorPvPMgr()
     for (OutdoorPvPSet::iterator itr = m_OutdoorPvPSet.begin(); itr != m_OutdoorPvPSet.end(); ++itr)
     {
         (*itr)->DeleteSpawns();
+        delete *itr;
     }
 }