set secret tag to option stack_domain_admin_password

[Ethan Lynn]

Currently stack_domain_admin_password is not a secret option in heat codes, and it's value will display in heat log.
https://github.com/openstack/heat/blob/master/heat/common/config.py#L73

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/134112

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/juno
Review: https://review.openstack.org/134596

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/134112
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=0307d0267713ed18309ecea5359f002d388eaf34
Submitter: Jenkins
Branch: master

commit 0307d0267713ed18309ecea5359f002d388eaf34
Author: Ethan Lynn <email address hidden>
Date: Thu Nov 13 12:46:39 2014 +0800

    Mark stack_domain_admin_password as a secret option

    Add secret=True to option stack_domain_admin_password,
    so that will avoid logging this option in engine.log.

    Closes-Bug: #1392162
    Change-Id: I04071f37a0053b969dc31a69e62ba9abb075c590

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/134596
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=a76ba370e8a8d61dd2363d2fd4c082466166257f
Submitter: Jenkins
Branch: stable/juno

commit a76ba370e8a8d61dd2363d2fd4c082466166257f
Author: Ethan Lynn <email address hidden>
Date: Thu Nov 13 12:46:39 2014 +0800

    Mark stack_domain_admin_password as a secret option

    Add secret=True to option stack_domain_admin_password,
    so that will avoid logging this option in engine.log.

    Closes-Bug: #1392162
    Change-Id: I04071f37a0053b969dc31a69e62ba9abb075c590
    (cherry picked from commit 0307d0267713ed18309ecea5359f002d388eaf34)