Remove obsolete nbtree page deletion comment.

Peter Geoghegan <pg@bowt.ie>

Commit: b8b3a276d453f5d561341021c93ec05b158f4c65
Author: Peter Geoghegan <pg@bowt.ie>
Date: 2019-08-27T21:01:43Z
Releases: 13.0
Remove obsolete nbtree page deletion comment.

Commit efada2b8e92, which made the nbtree page deletion algorithm more
robust, removed the concept of a half-dead internal page.  Remove a
comment about half dead parent pages that was overlooked.

Files