Fix support for DHCPV6 Relay multi vlan functionality. Make sure the relayed packet is received at correct interface.
How I did it
Bind a socket to each vlan interface's global and link-local address.
Socket binded to global address is used for relaying data from client to server and receiving data from servers.
Socket binded to link-local address is used for relaying data received from server back to the client.
This makes it possible to install the debug symbols if needed. Also install
the package into the debug version of sonic-dhcp-relay container.
Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>
