[3316] Merge branch 'master' into trac3316
Conflicts: src/bin/dhcp4/tests/dhcp4_test_utils.h src/bin/dhcp6/tests/dhcp6_srv_unittest.cc src/bin/dhcp6/tests/dhcp6_test_utils.h
Conflicts: src/bin/dhcp4/tests/dhcp4_test_utils.h src/bin/dhcp6/tests/dhcp6_srv_unittest.cc src/bin/dhcp6/tests/dhcp6_test_utils.h