ansible_2_6: 2.6.17 -> 2.6.20

This addresses the following security issues:

  * CVE-2019-14846 - Several Ansible plugins could disclose aws
    credentials in log files. inventory/aws_ec2.py, inventory/aws_rds.py,
    lookup/aws_account_attribute.py, and lookup/aws_secret.py,
    lookup/aws_ssm.py use the boto3 library from the Ansible process. The
    boto3 library logs credentials at log level DEBUG. If Ansible's
    logging was enabled (by setting LOG_PATH to a value) Ansible would set
    the global log level to DEBUG. This was inherited by boto and would
    then log boto credentials to the file specified by LOG_PATH. This did
    not affect aws ansible modules as those are executed in a separate
    process. This has been fixed by switching to log level INFO
  * Convert CLI provided passwords to text initially, to prevent unsafe
    context being lost when converting from bytes->text during post
    processing of PlayContext. This prevents CLI provided passwords from
    being incorrectly templated (CVE-2019-14856)
  * properly hide parameters marked with no_log in suboptions when
    invalid parameters are passed to the module (CVE-2019-14858)
  * resolves CVE-2019-10206, by avoiding templating passwords from
    prompt as it is probable they have special characters.
  * Handle improper variable substitution that was happening in
    safe_eval, it was always meant to just do 'type enforcement' and have
    Jinja2 deal with all variable interpolation. Also see CVE-2019-10156

Changelog: https://github.com/ansible/ansible/blob/9bdb89f740a87bcf760424577ce18a8f68d7a741/changelogs/CHANGELOG-v2.6.rst