socketeutils: extend receive_responses to handle other netlink types

socketeutils: extend receive_responses to handle other netlink types

This is the first patch in series of implementing NETLINK_GENERIC
protocol decoder.

receive_responses was written for decoding kernel responses of type
SOCK_DIAG_BY_FAMILY, other types were ignored.

This change makes the type of netlink response a parameter
so the function can be used for other types of communication.

* socketutils.c (receive_responses): add a new parameter
expected_msg_type to handle types other than SOCK_DIAG_BY_FAMILY.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>