#77 SLPDKnownDAGenerateMyDAAdvert() returns random data on error

[Pekka Vuorela]

SLPDKnownDAGenerateMyDAAdvert() function does not
generate DA advert beyond error code if the error code
is not 0. This means that the rest of the packet
remains unitilialized and in theory may contain
confidential data from slpd running with root privileges.

Attached patch does a memset to zero before creating
the DA advert packet.

[Pekka Vuorela]

patch to the bug