A value of the '--config-drive' option must be a boolean value
on the 'nova boot' command because nova accepts a boolean value
only for the 'config_drive' parameter.
So add a check for the '--config-drive' option on the 'nova boot'
command.
Fix a description for 'config_drive' parameter
in the 'create' method of the novaclient.v2.ServerManager class.
Change-Id: Ic6e65139302fbb662fb6ba60e73633dad8ffb72e
Closes-Bug: #1825061
d1c5dc61d6