Bug: saved game info is not updated when overwriting a save

[PawelS]

OS: Windows 7 64-bit
Wesnoth version: 1.9.12

How to reproduce:

1. Start a campaign.
2. Save the game, entering a name for it (for example 'test').
3. Start another campaign.
4. Save the game under the same name as before, overwriting the previous save.
5. Go to Load Game and select the 'test' game. The minimap and other info (campaign name, difficulty, turn number) will refer to the game you first saved under that name, not to the one you last saved.

It's only the information at the loading screen which is not updated, the game loads normally. Deleting userdata\save_index.gz fixes this problem, so it seems the data is not updated in this file when overwriting a saved game.

[AI]

I tracked down this bug ago myself a long while ago, and I believe the problem was that the new save info was simply appended to the index, without older information ever being cleared. I vaguely recall it being fixed though, so this may he a regression.

[doofus-01]

This behaviour has been pretty consistent since I've been paying attention - 1.3/1.4?, at least among released versions (I don't know about trunk). I noticed it because a map with UMC terrain always fails to load (the minimap, the scenario loads just fine) and gives an error, even after the map has been edited to have only mainline terrain. Probably not the same bug, but it is related, in the end.