Pin `rspec` to `~>3.3`
Pin `rspec` to `~>3.3`

RSpec 3.2 fails some tests related to `raise_error`. There were some
changes to that matcher in 3.3, so we're bumping to the latest version
to handle these cases.

See: http://rspec.info/blog/2015/06/rspec-3-3-has-been-released/

dpla/KriKri,dpla/KriKri,dpla/KriKri,dpla/KriKri