The behavior of server migrate command are different depending on
whether user specify --live option or not.
server migrate command will call live migration API if user specify
--live option.
Ohterwise server migrate command will call migration(cold migration)
API.
Now then, "--block-migraiton" option and "--disk-overcommit" option
only affect live-migration.
But, openstackclient doesn't warn user if user specify these options
without "--live".
But, user can't recognize that specifying options are ignored.
This patch adds a validation that checks whether or not user specify
these options without "--live".
Change-Id: Ifa278abb23ecdba4b13f3742998359ac74eb7ad4
Closes-bug: #1662755
7063ffb3ca