Fix #300 for match extension protocol

So... #300 fixed matching `-m (tcp|udp)` at the beginning of `-m
multiport` or `--dport` or `--sport` rules, but broke actual *creation*
of those rules because `-m (tcp|udp)` was used as an iptables argument,
which it is not.

This change removes the problematic argument from `@resource_map` and
instead just substitutes `-m (tcp|udp)` out of any existing rules before
matching. The `-m tcp` match extension arguments are optional anyway,
and not needed for iptables functionality and don't change the semantics
at all.
Merge pull request #302 from hunner/fix_match_extension

Fix #300 for match extension protocol