ofp-actions: Look inside write_actions for output ports and groups.

ofp-actions: Look inside write_actions for output ports and groups.

The out_port and out_group matches only looked at apply_actions
instructions, but my interpretation of the OpenFlow spec is that they
should also look inside write_actions.

This affected the output of (and in one case the correctness of) some
tests, so this updates them.

Reported-by: Gavin Remaley <gavin_remaley@selinc.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Reviewed-by: Simon Horman <simon.horman@netronome.com>