class Bundler::RubygemsIntegration

def backport_base_dir

Rubygems 1.8+
This backports base_dir which replaces installation path 
def backport_base_dir
  redefine_method(Gem::Specification, :base_dir) do
    return Gem.dir unless loaded_from
    File.dirname File.dirname loaded_from
  end
end