This commit adds a new pcap file to the test suite with an SPA packet after
99 other garbage packets. This can be used for pcap_dispatch() testing,
though this is not meant to be super instensive - it is just to ensure that
if a PCAP_DISPATCH_COUNT of, say, 10 is selected that the SPA is still seen
by fwknopd. This commit is in support of #110.