Fix unescaped backslash in previous pip list addition
Fix unescaped backslash in previous pip list addition

Ref: https://github.com/stankevich/puppet-python/pull/331

Fixed lax unescaped backslash to make it pass tests.

stankevich/puppet-python,ghoneycutt/puppet-python,stankevich/puppet-python,ghoneycutt/puppet-python