Enhancement: Pin python dependencies for development and testing

[samrocketman]

In order to test reliably, I recommend pinning your Python pip dependencies. virtualenv is recommended for this practice.

#create a .venv directory in the current directory
virtualenv --python $(type -P python2.7) .venv
#activate the virtual environment
source .venv/bin/activate
#all python pip changes only happen in the virtualenv .venv directory
#upgrade the version of pip
pip install -U pip
pip install ansible
pip freeze > requirements.txt

See also:

• More info about requirements.txt.
• More info about virtualenv.

This method makes for more reliable and transparent testing/development.

[samrocketman]

If the dev-sec team is open to this idea I'm willing to create a PR with suggested changes.

[rndmh3ro]

As of right now this is not needed for the ansible roles as they're tested with test-kitchen and Ansible is installed inside the vm/container.

However if we're to use molecule in the future, we should pin the dependencies. So I'm closing this in favor of #128, as it should be done there.