Added rosdep key rake-compiler to ruby.yaml

The newest version of [orogen](https://github.com/orocos-toolchain/orogen/tree/toolchain-2.8) now depend on `rake` and `rake-compiler` and we would need the new key for release in indigo.
@cottsay already added the `rubygem-rake-compiler` package to the `rake` key in d01c285282604f17bed03801d82ccd62f6d2a1f3, but only for Fedora.