Description of problem: If a Quantum subnet is created with DHCP enabled (the default), then the DHCP agent will create a tap device for the treating ports on the subnet. When this subnet is deleted the tap device is not deleted. Version-Release number of selected component (if applicable): How reproducible: Alway Steps to Reproduce: 1. Create network 2. Create subnet on network 3. Delete network (the tap device should be deleted) Actual results: Expected results: Additional info: