dhcrelay listen at all ifs but should only on dedicated ifs

[Patrick Cervicek]

> I´m running dhcrelay 4.3.5
>
> My start line is
> # dhcrelay -4 -d -iu br_TB104_TMN  -id br_TB104_DUT 10.160.50.50
> But dhcrelay is listen  on all if´s like I specified nothing specific
>

>     Listening on LPF/br_TB104_DUT/42:b9:9b:1e:1c:c9
>     Sending on   LPF/br_TB104_DUT/42:b9:9b:1e:1c:c9

>     Listening on LPF/br_TB104_TMN/7a:59:88:45:a6:23
>     Sending on   LPF/br_TB104_TMN/7a:59:88:45:a6:23
>     Listening on LPF/br_TB104_TMN/7a:59:88:45:a6:23
>     Sending on   LPF/br_TB104_TMN/7a:59:88:45:a6:23


It is confusing to me, that br_TB104_TMN is producing 4 lines, and
br_TB104_DUT is producing 2 lines.

Please start with the corrected startline and provide the output again.