By default, the alternative installed by `openvswitch-switch`
packages shadows (higher prio) `openvswitch-switch-dpdk` version,
e.g. for UCA Pike packages:

$ update-alternatives --query ovs-vswitchd
Alternative: /usr/lib/openvswitch-switch-dpdk/ovs-vswitchd-dpdk
Priority: 50
Alternative: /usr/lib/openvswitch-switch/ovs-vswitchd
Priority: 100

To avoid confusion, when DPDK is enabled and ovs-vswitchd-dpdk
should be used, remove the alternative for classic ovs-vswitchd
(which can easily be re-eneabled later if needed).

Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>