Fix service monitor virtual machine manager

- Ensure delete of VMs only if find is succesful
- Fix shared instance-ip delete on VMI delete. Ensure that all
  VMIs for the instance IP are deleted before deleting instance-ip

Change-Id: I3297bf4c509d3c66dc5845664f699a771b90c008
Closes-Bug: #1333810
Merge "Fix service monitor virtual machine manager"