Interfaces check doesn't honor admin port status

If using SNMPv1 with a network device, the admin state of a port is not honored.

This could “easily” be fixed by the “interfaces” check honoring the if64adm section (disabled by default “to save traffic”), since it is a misnomer and doesn’t actually need 64 bit (it’s actually located on the same MIB tree as the 32 bit counters). Currently, the if64adm section is only honored by the if64 check.