This plugin was using a deprecated function, vercmp_numbers(),
that wasn't actually working properly because the call to
'deprecated' at the beginning was causing garbage to be
returned to the caller. For example, this was always in
stack.sh.log when using OVS:
.../lib/neutron_plugins/ovs_base: line 57: [: too many arguments
Update to use vercmp() like all other users in devstack, and
remove all the old code.
Change-Id: I352362cf59e492fa9f7725190f0243f2436ac347