pg_upgrade:  Handle default_transaction_read_only settings

Setting default_transaction_read_only=true could prevent pg_upgrade from
completing, so prepend default_transaction_read_only=false to
PGOPTIONS.
Editorial corrections to the October 2013 minor-release notes.

This is mostly to fix incorrect migration instructions: since the preceding
minor releases advised reindexing some GIST indexes, it's important that
we back-link to that advice rather than earlier instances.

Also improve some bug descriptions and fix a few typos.

No back-patch yet; these files will get copied into the back branches
later in the release process.