RHEV-M: avoid failure of GET instance details

  A backtrace was sporadically produced for a
  GET /api/instance/<instance id>

  When one instance is being destroyed during a GET for
  another instance, a backtrace is produced. This is because
  a query for all instances (vms) was being done. The list of
  all instances is gathered, one instance is destroyed, then the
  list contained an invalid instance ID which when queried
  produced
  "Entity not found: id "

  Fixes https://issues.apache.org/jira/browse/DTACLOUD-462

  This change also caused automated VCR test failures which
  has resulted in the re-recording of those tests. The new
  recording has instituted changes to prevent the exposure
  of test bed credentials.
TrackedAt: http://tracker.deltacloud.org/patch/2db40fc62c97d9333a69dd1d94a37e09693f3b72