Using ctl paths we can put all the stuff, related to net/core/
sysctl table, into one file and remove all the references on it.

As a good side effect this hides the "core_table" name from
the global scope :)
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>