Cleanup `spec/lib/extracts_path_spec.rb`

There is duplicated code in spec/lib/extracts_path_spec.rb:

    context 'path contains space' do
      let(:params) { { path: 'with space', ref: '38008cb17ce1466d8fec2dfa6f6ab8dcfe5cf49e' } }
      it 'is not converted to %20 in @path' do
        assign_ref_vars
        expect(@path).to eq(params[:path])
      end
    end

and also similar code, but different, e.g. describe '#assign_ref_vars' do in CE bu describe '#assign_ref' do in EE...