multipath: make path devices readonly again.

Path device fds were changed to be opened read/write when the mpathpersist code was added. However, I have talked with Vijay, and this doesn't appear to be necessary for mpathpersist to work correctly. If the path fds are opened read/write, when the are closed a change uevent is triggered, which was causing problems during shutdown with LVM on top of multipath devices. This patch reverts them to being read-only again.

---
 libmultipath/discovery.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: multipath-tools-130109/libmultipath/discovery.c
===================================================================
@@ -886,7 +886,7 @@ pathinfo (struct path *pp, vector hwtabl
 	 * fetch info not available through sysfs
 	 */
 	if (pp->fd < 0)
-		pp->fd = open(udev_device_get_devnode(pp->udev), O_RDWR);
+		pp->fd = open(udev_device_get_devnode(pp->udev), O_RDONLY);
 
 	if (pp->fd < 0) {
 		condlog(4, "Couldn't open node for %s: %s",