pipes.c: fix English in a comment

"Has not" + noun is obsoleted and very rare English. Fix it.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

pipes.c

@@ -11,7 +11,7 @@
 /* The sequence of objects which should be restored:
  * pipe -> files struct-s -> fd-s.
  * pipe_entry describes  pipe's file structs-s.
- * A pipe has not own properties, so it has not own object.
+ * A pipe doesn't have own properties, so it has no object.
  */
 
 struct pipe_info {