selftests: tc-testing: drop test on missing tunnel key id

After merge of commit 80ef0f22

 ("net/sched: act_tunnel_key: Allow
key-less tunnels"), act_tunnel_key does not reject anymore requests to
install 'set' rules where the key id is missing. Therefore, drop the
following TDC testcase:

 ba4e - Add tunnel_key set action with missing mandatory id parameter

because it's going to become a systematic fail as soon as userspace
iproute2 will start supporting key-less tunnels.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>