ipc: change kern_ipc_perm.deleted type to bool

struct kern_ipc_perm.deleted is meant to be used as a boolean toggle, and
the changes introduced by this patch are just to make the case explicit.

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Acked-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>