Change dns snooper timeout to avoid spinning in pcap
Change dns snooper timeout to avoid spinning in pcap

The previous code seems to be relying on a 64-bit to 32-bit conversion
working in a certain way; when gopacket was changed to cast the value
explicitly it starts returning immeditely from pcap.

weaveworks/scope,weaveworks/scope,weaveworks/scope,weaveworks/scope,weaveworks/scope,weaveworks/scope