MINOR: http-rules/tcp-rules: Call the defined action function first if defined

MINOR: http-rules/tcp-rules: Call the defined action function first if defined

When TCP and HTTP rules are evaluated, if an action function (action_ptr field
in the act_rule structure) is defined for a given action, it is now always
called in priority over the test on the action type. Concretly, for now, only
custom actions define it. Thus there is no change. It just let us the choice to
extend the action type beyond the existing ones in the enum.