Sonar 3.4.1 server does not start on Gentoo Linux - no such file to load -- auto_gem

Hi Evgeny,

I have fixed an issue where when I upgraded to Sonar 3.4.2, when starting 
the sonar init script the server hangs with the error:

"application initialization failed: no such file to load -- auto_gem" 

As suggested in: http://bb10.com/java-sonar-general/2012-11/msg00028.html
The environment variable RUBYOPT should be cleared.

This pull request implements clearing RUBYOPT