Game crash when restarting

Calling `love.event.quit "restart"` crashes the game with Multiplayer installed, with a stacktrace as such:
```
INFO - [G] Error: [love "boot.lua"]:48: Failed to initialize filesystem: already initialized
stack traceback:
[C]: in function 'init'
[love "boot.lua"]:48: in function <[love "boot.lua"]:42>
[C]: in function 'xpcall'
[love "boot.lua"]:357: in function <[love "boot.lua"]:355>
[C]: in function 'xpcall'
```

The easiest way to trigger this behavior is by toggling a mod on or off in Steamodded's in-game mod manager.

Reproduce the crash by toggling a mod in Steamodded's in-game mod manager, then trace the restart path from love.event.quit "restart" and the reported love/boot.lua filesystem initialization error. Done means restarting after a mod toggle no longer crashes and the game initializes normally.

Written by the indexing model from the issue text.