Custom rubygems should not be needed for >= 2

[Bob van der Linden]

Currently all ruby builds get a custom rubygems version copied into the build. This shouldn't be needed because Ruby itself nowadays have rubygems (and other repositories) copied into the repo already.

This will make the builds more in line with what Ruby intended and more in line with builds from other distros. It also avoids having to match up the right rubygems for the right ruby versions.

Removing this will cause a rebuild of all ruby versions.

[Bob van der Linden]

This was resolved by #39