Revert to using OVS default OpenFlow versions.
Revert to using OVS default OpenFlow versions.

It makes sense to follow Open vSwitch's lead here.
OVS 2.3 enables OpenFlow 1.0 through 1.3 by default.
OVS 2.0 has incomplete support for 1.3, but you can enable
it with protocols=OpenFlow13

mininet/mininet,mininet/mininet,mininet/mininet