Add OVS cleanup utility
Add OVS cleanup utility

Fixes bug 1091605

The utility should be called after rebooting an appliance. This
will purge the openvswicth of configured tap devices.

A configuration variable quantum_ports has been added. This is
by default True which indicates that only Quantum ports will be
deleted from the OVS. If this is set as False then all ports on the
bridge will be deleted.

Change-Id: I442f64cf82f95bfa99d7765eb09db1ce2ecf602e

stackforge/networking-bigswitch,wolverineav/networking-bigswitch,openstack/networking-bigswitch,wolverineav/networking-bigswitch,openstack/networking-bigswitch,stackforge/networking-bigswitch