Remove OpenStack config found in clouds.yaml

Remove OpenStack config found in clouds.yaml

We can now reuse configuration already existing in our clouds.yaml to
run packer builds against instead of duplicating that effort in var
files. Packer added this feature in version 1.2.5.

Packer does not read profiles so we have to explicitly pass
some variables that would normally be pulled from profiles such
as auth_url, user_domain_name, and project_domain_name.

  linuxfoundation:
    profile: vexxhost
    auth:
      auth_url: 'https://auth.vexxhost.net/v3/'
      project_name: abc
      username: 123
      password: v1.2.3
      user_domain_name: Default
      project_domain_name: Default
    region_name: ca-ymq-1

Issue: RELENG-1205
Change-Id: I9f05ec1c430a9261e45dc801e5e5aab52a22cfba
Signed-off-by: Thanh Ha <thanh.ha@linuxfoundation.org>