Comment 2 for bug 1667266

Reviewed: https://review.openstack.org/438141
Committed: https://git.openstack.org/cgit/openstack/python-openstackclient/commit/?id=7a7bb06377c96f7bfc2c371aa2ff726ee364a9db
Submitter: Jenkins
Branch: master

commit 7a7bb06377c96f7bfc2c371aa2ff726ee364a9db
Author: Rui Chen <email address hidden>
Date: Fri Feb 24 16:48:05 2017 +0800

    Make block-device-mapping more stable and clear

    The patch fix the following issues:

    1. ValueError is raised if input don't contain "=". Sometimes the whole
    "server create" command is very complex, it's difficult to find out root
    reason directly.
    2. Don't support to add block device from snapshot, like:
    --block-device-mapping
    vdb=0c8ae9d8-cadc-4a23-8337-4254614d277e:snapshot:1, it's supported by
    novaclient, but not in osc.
    3. If input "vdb=", not add any mapping information, the server will be
    launched successfully, not raise error message to let use add
    volume/snapshot id, just ignore "--block-device-mapping" option.
    4. The help message of "block-device-mapping" option is so simple, need
    to add some details about how to add <type>, <delete_on_terminate>
    contains.

    Change-Id: Ib7f7a654c3dc2a8272545f168b4c4ced230ce39e
    Depends-On: Ib37913891bbf7a31b570404c4668c490d5ac859b
    Closes-Bug: #1667266