CA-81025: Remove archived RRDs after cross-pool migration

Destroying the VM using the API and not just the database calls causes the
removal of the archived RRDs on the master.

Signed-off-by: Si Beaumont <simon.beaumont@citrix.com>
Merge pull request #2015 from simonjbeaumont/ca-81025

CA-81025: Remove archived RRDs after cross-pool migration