added configuration for Ruby 2.1 support in spec

add Ruby 2.1 support in Spec tests

Debian bugs:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=746084
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=747723
Merge pull request #94 from hggh/ruby21

added configuration for Ruby 2.1 support in spec