minor fix, testing with pfring-aware libpcap (commented out)

git-svn-id: https://svn.ntop.org/svn/ntop/trunk/nDPI@7865 a02cd0c1-8e76-42e1-a119-56f9641475e2
Spotify dissector improvements

git-svn-id: https://svn.ntop.org/svn/ntop/trunk/nDPI@7867 a02cd0c1-8e76-42e1-a119-56f9641475e2