Core/Guild: avoid data integrity problems wrapping delete+insert statements in a transaction

Source/Game/Handlers/CharacterHandler.cs

@@ -1706,7 +1706,7 @@ namespace Game
                         {
                             Guild guild = Global.GuildMgr.GetGuildById(result.Read<ulong>(0));
                             if (guild)
-                                guild.DeleteMember(factionChangeInfo.Guid, false, false, true);
+                                guild.DeleteMember(trans, factionChangeInfo.Guid, false, false, true);
                         }
 
                         Player.LeaveAllArenaTeams(factionChangeInfo.Guid);

Source/Game/Handlers/PetitionsHandler.cs

@@ -482,14 +482,17 @@ namespace Game
 
             Guild.SendCommandResult(this, GuildCommandType.CreateGuild, GuildCommandError.Success, name);
 
+            SQLTransaction trans = new SQLTransaction();
+
             // Add members from signatures
             for (byte i = 0; i < signatures; ++i)
             {
-                guild.AddMember(ObjectGuid.Create(HighGuid.Player, result.Read<ulong>(0)));
-                result.NextRow();
-            }
+                guild.AddMember(trans, ObjectGuid.Create(HighGuid.Player, result.Read<ulong>(0)));
 
-            SQLTransaction trans = new SQLTransaction();
+                // Checking the return value just to be double safe
+                if (!result.NextRow())
+                    break;
+            }
 
             stmt = DB.Characters.GetPreparedStatement(CharStatements.DEL_PETITION_BY_GUID);
             stmt.AddValue(0, packet.Item.GetCounter());