Remove unnecessary comment.

Author: Vik Fearing
Discussion: https://postgr.es/m/150d3e9f-c7ec-3fb3-4fdb-def47c4144af%402ndquadrant.com

src/backend/access/nbtree/nbtpage.c

@@ -268,7 +268,7 @@ _bt_update_meta_cleanup_info(Relation rel, TransactionId oldestBtpoXact,
  *		its location from the metadata page, and then read the root page
  *		itself.  If no root page exists yet, we have to create one.  The
  *		standard class of race conditions exists here; I think I covered
- *		them all in the Hopi Indian rain dance of lock requests below.
+ *		them all in the intricate dance of lock requests below.
  *
  *		The access type parameter (BT_READ or BT_WRITE) controls whether
  *		a new root page will be created or not.  If access = BT_READ,