Fix a typo in comment for _get_ofp_version
Fix a typo in comment for _get_ofp_version

OpenFlow11 -> OpenFlow10

Change-Id: I2a501ccd32f5f7a39fd4bc746f00ca3f67bd98c1

richliu/devstack,noironetworks/devstack,Mahito/devstack,group-policy/devstack,bswartz/devstack,bigswitch/devstack,bigswitch/devstack,noironetworks/devstack,openstack-dev/devstack,bswartz/devstack,richliu/devstack,Mahito/devstack,nawawi/openstack,dtroyer/devstack,nawawi/openstack,group-policy/devstack,openstack-dev/devstack,dtroyer/devstack