Update contiki

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
tcp-socket: Fix uninitialized data in struct tcp_socket

Some data could be used uninitialized in this structure.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
tcp-socket: Remove unused data in struct tcp_socket

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
http-socket: Fix uninitialized data in struct http_socket

Some data could be used uninitialized in this structure.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>