Fix bogus argument validation

* The comparaison couldn't ever not match. Based on the comment above the
  function, I made it so that flags must contain at least one of B_WATCH_NAME,
  B_WATCH_STAT or B_WATCH_ATTR

CID 2586

src/kits/storage/NodeMonitor.cpp

@@ -38,8 +38,8 @@
 status_t
 watch_volume(dev_t volume, uint32 flags, BMessenger target)
 {
-	if ((flags | B_WATCH_NAME) == 0 && (flags | B_WATCH_STAT)
-		&& (flags | B_WATCH_ATTR))
+	if ((flags & B_WATCH_NAME) == 0 && (flags & B_WATCH_STAT) == 0
+		&& (flags & B_WATCH_ATTR) == 0)
 		return B_BAD_VALUE;
 
 	flags |= B_WATCH_VOLUME;