jenkins: add owners tool to userid-validation flow

Run the 'owners' tool during the userid-validation so that
owners and reviewers are automatically added by Jenkins.

Fix a few minor issues with the 'owners' tool:

  - Switch the 'push-args' option from BooleanOptionalAction since
    this isn't supported in the Python version on the Jenkins
    controller.

  - Handle empty 'matchers' statements.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ib496c5874a532299ecf821345c8c25d87a21f3f1
2 files changed