staging:lustre: use available kernel wrappers in lib-socket.c

Instead of handling calls to struct proto ourselves we can use
equivalent kernel wrappers. No wrapper exist for unlocked ioctl
handling so we create one here for our use. I expect some day
that function will be integrated into sock.c.

Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>