vsenv, vs90wrapper: delete

[grahamc]

Motivation for this change

Two ancient "packages" which were experimental from @svanderburg in 2010. If you accidentally install visual-studio-9.0 thinking it was vscode, you'd have a bad time because it breaks build-env:

grahamc@Morbo> nix-env -i visual-studio-9.0
warning: there are multiple derivations named 'visual-studio-9.0'; using the first one
installing 'visual-studio-9.0'
these paths will be fetched (0.00 MiB download, 0.00 MiB unpacked):
  /nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0
copying path '/nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0' from 'https://cache.nixos.org'...
building '/nix/store/m7l5nkq570mfdx42h1jmi3c2v748vx0z-user-environment.drv'...
created 1 symlinks in user environment

grahamc@Morbo> nix-env -iA nixos.elinks
warning: name collision in input Nix expressions, skipping '/home/grahamc/.nix-defexpr/channels_root/nixos'
installing 'elinks-0.12pre6'
...
error: getting status of '/nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0/bin/vcbuild.exe': No such file or directory
builder for '/nix/store/z37fy73whp6njv9k5k126ifk8117fxgb-user-environment.drv' failed with exit code 1
error: build of '/nix/store/z37fy73whp6njv9k5k126ifk8117fxgb-user-environment.drv' failed

because indeed:

[130] grahamc@Morbo> ldd /nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0/bin/vcbuild.exe
ldd: /nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0/bin/vcbuild.exe: No such file or directory

[1] grahamc@Morbo> file /nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0/bin/vcbuild.exe
/nix/store/clkjwx5vcdv2vx6gfy6j8jzm9syr9i8x-visual-studio-9.0/bin/vcbuild.exe: broken symbolic link to /cygdrive/c/Program Files/Microsoft Visual Studio 9.0/VC/vcpackages/vcbuild.exe

anyway, I'm thinking @svanderburg doesn't need this anymore, or have /cygdrive on his laptop anymore :)

[truthadjustr]

Thanks for this fix. I attached below an actual session record error that tormented me for sometime:

https://asciinema.org/a/TeB0ZP18HFxM17MkmJoy1RK6G