Fix in-game masterserver listing

When masterserver_room_id was introduced, the code became a bit of a mess since the old ms_RoomId variable became the previous value rather than the current one, which in combination with defaulting to 0 rather than -1 lead to a bunch of state issues. All of this is cleaned up and should works as intended now.

added Bug Regression labels

approved this merge request

changed milestone to %2.2.15

merged

mentioned in commit 5f66e675