This patch addresses JIRA DTACLOUD-462. The Indication: A backtrace was produced from a GET /api/instance/<instance id>
The Problem: If a different instance is being destroyed during a GET for a different instance a backtrace is produced. This is because a query for all instances (vms) was being done. The list of all instances is gatherd, one instance is destroyed, then the list contained an invalid instance ID which when queried produced "Entity not found: id " The fix: To query only one instance (vm) when the instance ID is provided. Additionaly: During testing I discovered the MIGRATING status being returned by RHEVm that we had not been handling. RHEVm may have added other status we need to handle. This will be tracked in JIRA: DTACLOUD-485
