set default drb_port in RSpec::Configuration
Created by: charlietanksley
The documentation says this is set to 8989 by default, but it is only set in RSpec::Core::DRbCommandLine. This remedies that.
See https://github.com/rspec/rspec-core/blob/master/lib/rspec/core/configuration.rb#L97 for where the default is specified. Run my spec file to see that it isn't.