Staging: epl: do not use CLONE_SIGHAND with allow_signal()

Not sure this patch is really needed since kernel_thread() is deprecated
(and checkpatch.pl complains).

But we should not use kernel_thread(CLONE_SIGHAND) if we are going to play
with signals.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>