This patch reverts .
The code wasn't accounting for VLAN provider networks, as stated in the
bug #1842988, DVR won't work if the provider network (where the FIP is
created) is VLAN.
There was also an incosistency in how the external_mac was set for the
VLAN networks. Upon creating the FIP the code was checking for the
network type and not setting the external_mac attribute in case the
network was VLAN type. But, if the port went down and up again (e.g if
you reboot the VM) the event handler that set/unset the external_mac 
wasn't check for the type. This is how people worked around the DVR
problem (as stated in bug #1842988).
For more information see bug #1842988.
Signed-off-by: Lucas Alvares Gomes <email@example.com>
(Cherry-picked from Neutron Ifb795626dc9c2ac4f0104f491dd38c9b4cc902c9)
(cherry picked from commit f9b1dffada)