Bug#813318: libneon27-gnutls: Undefined symbol: gnutls_mac_set_priority

[Antonio Froio]

This bug affects also my system (testing ), with libneon27-gnutls version
0.30.1-2+b2 and isc-dhcp-common version 4.3.3-5, so I would deduce that the
bug is not related to those upgrades.

Antonio