Bug fix tc action drop

Bug fix tc action drop

>>That command is from a script that used to work with iproute2-ss020116
>>(2002!), which had the following in tc/m_police.c:
>>
>>210     } else if (strcmp(*argv, "action") == 0) {
>>211             NEXT_ARG();
>>212             if (get_police_result(&p.action, &presult, *argv)) {
>>
>>I don't know when that bit was dropped, but it used to be there. :-)
>
>
>
> Indeed, I missed that. I'll fix up the patch ..

OK this patch fixes parsing of "action ...". I've removed
the erroring on unknown arguments again since in that case
the caller should continue parsing.