Update ruby193-rubygem-therubyracer to 0.12.0-2.el6

- new package built with tito
- Remove the libv8 gem after initial compilation so execjs will load it
Update rubygem-therubyracer to 0.12.0-2.fc18

- new package built with tito
- Remove the libv8 gem after initial compilation so execjs will load it