udev: fix uevent-helper disable
Make sure that /proc/sys/kernel/hotplug exists before trying to disable
the uevent-helper mechanism.
Since kernel commit
86d56134f1b6 ("kobject: Make support for
uevent_helper optional.") the kernel can be built without uevent-helper
support. In this case /proc/sys/kernel/hotplug does not exist and the
current sysvinit script fails with
/etc/rcS.d/S04udev: line 132: can't create /proc/sys/kernel/hotplug: nonexistent directory
when trying to disable the uevent-helper mechanism during boot.
Note that a single NULL-character has always been sufficient to disable.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ross Burton <ross.burton@intel.com>
