Add MD5 for ruby-2.1.0-rc1.
Replace ruby-2.1.0-preview2 with ruby-2.1.0-rc1.
do not change rights if there is no need for that
Merge pull request #2443 from havenwood/2.1.0-rc1

Add Ruby 2.1.0 RC1.
change the default patchlevel for 2.1.0, update #2443
make sure run_gem_wrappers_regenerate is used also in rubinius, update #2434