[master] Merge branch 'trac5076' (flex/bison for control agent)

diff --cc src/bin/dhcp4/tests/ctrl_dhcp4_srv_unittest.cc
Simple merge

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

diff --cc src/bin/dhcp6/tests/parser_unittest.cc
Simple merge

diff --cc src/lib/dhcp/tests/duid_factory_unittest.cc
Simple merge