Bug#919467: steam: data loss when switching from Valve's steam package

[Simon McVittie]

Package: steam
Version: 1.0.0.56-2
Severity: important

Steps to reproduce (have a backup first):

* Install Valve's steam package from http://repo.steamstatic.com/steam/
* Run Steam
* Log in and save password
* Install and run some games
* Remove Valve's steam and steam-launcher packages
* Install Debian's steam and steam-devices packages
* Run Steam again

Expected result:
* Saved password is used again
* Installed games remain installed
* Saved games, etc. remain intact

Actual result:
* Steam directory is wiped and reinstalled
* Saved password is lost
* Installed games appear to be lost (actually they continue to take up
  space in ~/.local/share/Steam but are not accessible through the GUI)
* Saved games, etc. appear to be lost (actually they continue to take up
  space in ~/.local/share/Steam but are not accessible through the GUI)

This is because the Debian /usr/games/steam wrapper script not
only installs into ~/.steam (#916303), but does not recognise other
installation locations.

I think we can solve this by using a variation of the patch I attached
to #916303. If Michael is unwilling to switch the default for new
installations to ~/.local/share/Steam, then the next best thing is to
continue to default to ~/.steam for new installations, but respect the
existing installation path for existing installations.

I was tempted to give this 'grave' severity (because it's data loss),
but switching between Valve's packages and Debian's is not straightforward,
so it's a somewhat niche situation.

    smcv