Don't register empty sysctl dirs in /proc/sys.

Don't register empty sysctl dirs in /proc/sys.
They would be removed after registering some other sysctl(s) in the
same directory (e.g. rtc in /proc/sys/dev) and unregistering all of
them (then initially empty e.g. /proc/sys/dev disappears).
After disappearing of directory topdir ->de (for "dev") points to
structure which has been freed.
It's harmless in vanilla 2.4, but with grsecurity causes an Oops
on numeric sysctls referring to removed directory (even with all
grsecurity features disabled, only patch applied).

The same issue seems to exist in 2.6, and _probably_ can cause similar
problems in selinux.

Changed files:
    linux-2.4-sysctl-empty.patch -> 1.1