Update sqlite upgrade documentation

This makes small changes to the sqlite upgrade documentation.  As a
bonus change, this also deletes an unused file that should have been
removed when the sqlite build process began using trunk-stable flags.

Test: documentation only

Flag: DOCS_ONLY
Bug: 337329990
Change-Id: Ife1b486ea46e68ab7b9e9d1f9a71c8892da4955d
2 files changed