'st2_version' Overhaul

[arm4b]

The goal is consistent functionality incl. naming when it comes to specifying Stackstorm version to install to allow users achieve what they want: major/minor/path version, auto-update, no-autoupdate, latest revision pin, etc.

• Fix version install syntax for apt/yum (done in dfb5588)
• Consider deprecating st2_revision since it doesn't work everywhere
  • apt install st2=2.2.1-5 (revision is required)
  • yum install st2-2.2.1 (revision could be omitted)
• Consistency: not every role contains st2_revision. Use everywhere or nowhere.
• Naming overhaul for st2_version: null, ``, latest, `present`, `*`
• Consider changing st2_version defaults to NO auto-update, as prod-friendly setting
• Research solution for Add logic for 'latest' st2_revision #111
• Better README with version install examples & tricks & describing diff apt/yum behavior to allow users achieve what they want (stable, patch, auto-update, no-autoupdate, latest revision pin)

[AndyMoore]

have just raised #159 to improve the documentation around the current situation

at the moment if you pin st2_version you must also pin mistral_version - when the above is done it'd be great if pinning stackstorm_version would do both st2 and st2mistral

also currently the way these are currently defined is different:

/etc/ansible/roles/stackstorm/roles/st2/tasks/main.yml: name: st2{{ '-' if ansible_pkg_mgr == 'yum' else '=' }}{{ st2_version }}-{{ st2_revision }} /etc/ansible/roles/stackstorm/roles/st2mistral/tasks/main.yml: name: st2mistral{{ '-' if ansible_pkg_mgr == 'yum' else '=' }}{{ st2mistral_version }}

st2 has a revision whereas st2mistral has it as part of the version