[Fontconfig] Patch: fix double free (spotted by Coverity)

[Patrick Lam]

Frederic Crozat wrote:
> The following patch fixes memory and file descriptor leaks (Coverity
> reports #777 and #1826) in error cases for FcDirScanConfig.
> 
> Please review this patch carefully, as I used goto for bail conditions
> and tried to call free functions only one time in the FcDirScanConfig
> code (to ease code review in the future).

I've committed a modified version of this patch.  I think it's correct.

pat