Refuse to detect unrar-free as valid option

[Gfy]

rescene/unrar.py will find unrar-free in /usr/bin/unrar on Linux, but this executable will fail on compressed RAR v3 files or higher. This is unusable for vobsub srr creation. The vobsub .srr file will be created, but no recursive srr creation occurs for the .sub rar and no languages.diz file will be created.

unrar 0.0.1 Copyright (C) 2004 Ben Asselstine, Jeroen Dekkers

http://serverfault.com/questions/380485/unrar-free-doesnt-work