microversion v2.25 will change parameter of os-migrateLive, this patch
adds supports to that changes.
os-migrateLive will abandon disk_over_commit and the default value of
block_migration will be set to `auto`
Depends-on: Ibb0d50f0f7444028ef9d0c294aea41edf0024b31
Implements: blueprint making-live-migration-api-friendly
Change-Id: I01b22593724616bc0a7793c509ecabf095d6927d