new manage_requirements argument to address issue 273

[rosenbergj]

No description provided.

[rosenbergj]

(My first ever pr; please be gentle...)

[ghoneycutt]

@rosenbergj thanks for contributing!

[ghoneycutt]

This also needs to be documented in the README.md

[rosenbergj]

Fixed.

[ghoneycutt]

Looks good. We also need some spec tests - See https://github.com/stankevich/puppet-python/blob/master/spec/defines/requirements_spec.rb

Add a block where you let params set manage_requirements to false and it should test that the file $requirements is not in the catalog

context "/requirements.txt" do
        let (:params) {{ :requirements => "/requirements.txt", :manage_requirements => false }}
        it { is_expected.not_to contain_file("/requirements.txt") }
      end

[rosenbergj]

Thank you!