sockets: Fix a few problems if compiled with DEBUG=1

sockets.c: In function ‘show_one_inet_img’:
sockets.c:151:2: error: format ‘%d’ expects argument of type ‘int’, but argument 9 has type ‘char *’ [-Werror=format]
sockets.c: In function ‘open_unix_sk_stream’:
sockets.c:925:10: error: unknown escape sequence: '\C' [-Werror]

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>