Fix DNS SRV responses and a small issue with NBNS queries and label length.

 - DNS SRV responses never had the code written to actually
   generate the dns_SRV_reply event.  Adding this required
   extending the event a bit to add extra information.  SRV responses
   now appear in the dns.log file correctly.

 - Fixed an issue where some Microsoft NetBIOS Name Service lookups
   would exceed the max label length for DNS and cause an incorrect
   "DNS_label_too_long" weird.
No longer accidentally attempting to parse NBSTAT RRs as SRV RRs.

The NetBios name service RFC (1002) specified NBSTAT (NetBios Status)
resource records to have identifier 0x0021.  The DNS SRV RFC specified
SRV records to have identifier 33.  Unfortunately those are the
same number. :)

We now check the resp port to handle this situation better so that
we won't be attempting to parse NBSTAT records as SRV (which
causes several weird messages).
Merge remote-tracking branch 'origin/topic/seth/dns-srv-fix'

* origin/topic/seth/dns-srv-fix:
  No longer accidentally attempting to parse NBSTAT RRs as SRV RRs.
  Fix DNS SRV responses and a small issue with NBNS queries and label length.

BIT-1147 #merged