Use MRI copy of Ruby Spec for trunk builds
Use MRI copy of Ruby Spec for trunk builds

Trunk branch often contains specific changes, which get
synchronized every month. It therefore can happen, that
the trunk build fails for several weeks, until the spec suite
is synchronized again.

larskanis/rubyinstaller2,oneclick/rubyinstaller2,oneclick/rubyinstaller2,larskanis/rubyinstaller2,oneclick/rubyinstaller2,larskanis/rubyinstaller2