#186654 - Two files with difference only in case are packaged in the build

Please review the fix for  
http://netbeans.org/bugzilla/show_bug.cgi?id=186654

Fix: Removed the ruby-debug gem (which provided the two files) from the 
pre-installed gems in the bundled JRuby. It should be noted that this 
does not affect Ruby debugging in the IDE; the gem is for command line 
debugging and was added in JRuby 1.5 as a convenience, users can still 
install it themselves if they wish (like before with JRuby 1.4/NB 6.8).

Verified in trunk by Petr Chytil.

Thanks,
Erno