Bump .ruby-version to 1.7.6.
Bump .ruby-version to 1.7.6.

mwiley/jruby-sandbox,omghax/jruby-sandbox,Telmate/jruby-sandbox,mwiley/jruby-sandbox,Telmate/jruby-sandbox,k-yamada/jruby-safe,k-yamada/jruby-safe,omghax/jruby-sandbox