Problems with luarock 3.0.2 under Windows

[osch]

see https://ci.appveyor.com/project/osch/experimental/build/0.3.2.37

luarocks 2.4.4 output:

Configuration files:
         System: c:/hererocks/luarocks/config-5.3.lua (ok)
         User  : C:/Users/appveyor/AppData/Roaming/luarocks/config-5.3.lua (not found)

luarocks 3.0.2 output:

Configuration files:
         System  : C:/Program Files/luarocks/config-5.3.lua (not found)
         User    : C:/Users/appveyor/AppData/Roaming/luarocks/config-5.3.lua (not found)

So somehow the system configuration file cannot be found.

Workaround:

    set LUAROCKS_CONFIG=c:\hererocks\luarocks\config-%LUA%.lua