[master] kea-dhcp4/6 now attempt to process packets with bad vendor options

    Merge branch 'trac5551'

diff --cc src/bin/dhcp4/dhcp4_messages.mes
Simple merge

diff --cc src/bin/dhcp4/dhcp4_srv.cc
Simple merge

diff --cc src/bin/dhcp4/tests/dhcp4_srv_unittest.cc
Simple merge

diff --cc src/bin/dhcp6/dhcp6_messages.mes
Simple merge

diff --cc src/bin/dhcp6/dhcp6_srv.cc
Simple merge