[tex-live] [TL 2013 pretest] Win32's fc-cache doesn't read the variable `FC_CACHEDIR` and `FONTCONFIG_PATH` in texmf.cnf file

[Qing Lee]

My OS is Win7 SP1 64-bit. It is an issue of TL 2013 pretest. In TL 2012, 
everything is OK.

If I change the value of `FONTCONFIG_PATH` in $TEXMFLOCAL/texmf.cnf, say

     FONTCONFIG_PATH = $TEXMFVAR/fonts/conf
     FC_CACHEDIR     = $TEXMFVAR/xetex-cache

and move the directory `conf` to `$TEXMFVAR/fonts` from 
`$TEXMFSYSVAR/fonts`. Then run fc-cache -v, it syas that

     C:\texlive>fc-cache -v
     Note that it needs some time to create caches,
     especially if there are many large font files.

     Fontconfig error: Cannot load default config file
     C:/texlive/2013/texmf-var/fonts/cache: cleaning cache directory
     fc-cache: succeeded

`FC_CACHEDIR` has the similar issue.