Revert parts of a previous transaction-fix (would create a nested transaction), add missing support for rollback in battleground-group creation

--HG--
branch : trunk

src/game/Group.cpp

@@ -116,7 +116,10 @@ bool Group::Create(const uint64 &guid, const char * name)
     }
 
     if (!AddMember(guid, name))
+    {
+        CharacterDatabase.RollbackTransaction();
         return false;
+    }
 
     if (!isBGGroup()) CharacterDatabase.CommitTransaction();
 
@@ -1288,7 +1291,7 @@ void Group::_setLeader(const uint64 &guid)
             "DELETE FROM group_instance WHERE leaderguid='%u' AND (permanent = 1 OR "
             "instance IN (SELECT instance FROM character_instance WHERE guid = '%u')"
             ")", GUID_LOPART(m_leaderGuid), GUID_LOPART(slot->guid)
-);
+        );
 
         Player *player = objmgr.GetPlayer(slot->guid);
         if (player)

src/game/Mail.cpp

@@ -354,8 +354,7 @@ void WorldSession::HandleMailReturnToSender(WorldPacket & recv_data)
     //we can return mail now
     //so firstly delete the old one
     CharacterDatabase.BeginTransaction();
-    CharacterDatabase.PExecute("DELETE FROM mail WHERE id = '%u'", mailId);
+    CharacterDatabase.PExecute("DELETE FROM mail WHERE id = '%u'", mailId);             // needed?
-                                                            // needed?
     CharacterDatabase.PExecute("DELETE FROM mail_items WHERE mail_id = '%u'", mailId);
     CharacterDatabase.CommitTransaction();
     pl->RemoveMail(mailId);

src/game/Player.cpp

@@ -17542,11 +17542,12 @@ void Player::SaveToDB()
     if (m_session->isLogingOut() || !sWorld.getConfig(CONFIG_STATS_SAVE_ONLY_ON_LOGOUT))
         _SaveStats();
 
+    CharacterDatabase.CommitTransaction();
+
     // save pet (hunter pet level and experience and all type pets health/mana).
     if (Pet* pet = GetPet())
         pet->SavePetToDB(PET_SAVE_AS_CURRENT);
 
-    CharacterDatabase.CommitTransaction();
 }
 
 // fast save function for item/money cheating preventing - save only inventory and money state