General: Reference the correct database version for 5.5.0 upgrades.

Follow up to [48121].

See #50413.
Built from https://develop.svn.wordpress.org/trunk@48122


git-svn-id: https://core.svn.wordpress.org/trunk@47891 1a063a9b-81f0-0310-95a4-ce76da25c4cd