BUG-954: Add support for Neutron port/network delete events for OF1.3

This commit will enable support for Neutron port delete and network delete events.
It will also enable flow cleanup and tunnel port delete for ovsdb using OF 1.3

Signed-off-by: Hsin-Yi Shen <hshen@redhat.com>
Change-Id: Ic848125d21abc44c796ef2b1675cca9e50630f76