src/bin/dhcp4/dhcp4_srv.*
    - dumpPackets() - new function that frees all cached and parked packets
    - Dhcpv4Srv::~Dhcpv4Srv() - added call to dumpPackets() for cleanliness

src/bin/dhcp4/json_config_parser.cc
    configureDhcp4Server() - added a call Dhcpv4Srv::dumpPackets()

src/bin/dhcp6/dhcp6_srv.*
    - dumpPackets() - new function that frees all cached and parked packets
    - Dhcpv6Srv::~Dhcpv6Srv() - added call to dumpPackets() for cleanliness

src/bin/dhcp6/json_config_parser.cc
    configureDhcp6Server() - added a call Dhcpv6Srv::dumpPackets()

src/lib/hooks/hooks_manager.h
    - clearParkingLots() - new convenience function for clearing
     all parking lots
    - clearParkingLotsInternal() - private impl of the above