The earlier code always tried to use TitleDatabase for getting
title names, but that didn't work for disc-based games, because
there was no way to get the maker ID.
There are some cases where overriding the opening.bnr names
isn't desirable, such as when someone has several modded
versions of a game that differ in names but not game IDs.
This seems like an oversight in the old code, because
what's the point of loading user files if the titles
in them are going to be ignored for nearly all games?
This commit fixes the issue by making the first LoadMap
variant not overwrite entries and making the constructor
do everything in the opposite order. An alternative solution
would be to make the second LoadMap variant overwrite entries.
