This patch adds a 'new_share_type_id' parameter to Share Migration,
where the destination share can be provisioned under a different
share type of choice.
Host-assisted migration handles it by creating a totally new share,
as before.
Driver-assisted migration handles by creating the destination
instance model with the new share type, the driver is responsible
for making the necessary changes to satisfy the provided model.
In order to accomplish this, a database change was required,
transferring the 'share_type_id' field from the 'shares' table
to the 'share_instances' table.
APIImpact
Partially implements: blueprint newton-migration-improvements
Change-Id: I3200eaaa5b66d9b8ce1cbd16c1658db8516c70fb
6dad1666de