Upgrade scripts to migrate aodh alarm data

Upgrade scripts to migrate aodh alarm data

In Newton, Aodh will be using its own mysql DB rather than
using ceilometer's mongo instance. This means we need to
migrate any existing alarm and alrm history data from
ceilometer DB to aodh mysqlDB. Upstream aodh provides us
with a aodh-data-migration utility. We need to invoke this
during the mitaka->newton upgrade procedure so data is
migrated as expected and aodh mysql backend takes over.

Closes-bug: #1611794

Change-Id: I17888b57ecf98cd83e92af2f9cdbead066b03aa3