Re: [PATCH] inet_diag: make config INET_DIAG bool

when inet_diag being compiled as module, inet_diag_handler_dump
set netlink_dump_control.dump to inet_diag_dump,so if module
inet_diag is unloaded,netlink will still try to call this function
in netlink_dump. this will cause kernel panic.

Another way to handle this to just get rid of inet_diag_exit
so that module can be loaded but not unloaded.