Gem installation fails due to packaged gems

Rake 0.9.6 comes bundled with ruby 2. However, I needed to build ruby-debug-ide 0.4.17.beta16 against rake 0.8.7. I tried uninstalling rake 0.9.6 but there is no way to do it. Using the following command does not list 0.9.6 as an option.

gem uninstall rake

So, now I had to find a way to tell the gem utility to use rake 0.8.7 instead of 0.9.6. A little reading showed that setting the RAKE environment variable could do this.

RAKE=/usr/lib/ruby/gems/2.0.0/gems/rake-0.8.7/bin/rake gem install ruby-debug-ide -v 0.4.17.beta16 --pre

The above  did not work for some reason. After that I tried the following and it worked.

RAKE=`bundle exec rake` gem install ruby-debug-ide -v 0.4.17.beta16 --pre