maint: Remove rspec options from the Rakefile

Having the Rakefile set RSpec options made it so that the .rspec
(spec.opts in RSpec < 2) file for personal RSpec preferences was
ignored.

It also caused the ci_reporter RSpec options to be ignored which meant
that Hudson couldn't get consumable output from our spec runs.

It's also about time Puppet had a project level .gitignore file so that
if people want personal rspec preferences (color or a different print
format for example) in a .rspec file, those changes don't actually get
checked in.

Paired-with: Jesse Wolfe