Refactor compute_utils to avoid db lookup

This simple change passes bdms into the following compute_utils function
to avoid it doing a database lookup:

  get_device_name_for_instance()

Related to bp/no-db-compute

Change-Id: I1475b184d8e88b700d606aaf77cc7cd21e83efbb
Merge "Refactor compute_utils to avoid db lookup"
Merge remote-tracking branch 'citrix/master' into build-temp