Ensure the RubyInstaller dir is always preferred.
Ensure the RubyInstaller dir is always preferred.

This avoids interference with rubies in msys env.

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