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
7a7bb06377