Backport fix for BZ #18928?

[Joseph Myers]

I think bumping the version number to 2.22.2 should imply making a 2.22.1 
release (which means updating the release checklist to make clear which 
bits apply to point releases, e.g. tagging and release tarballs and 
announcements, and which don't, e.g. branching - and probably also a 
variant of the release announcement that makes clear this is a point 
release with just a few bug fixes, not a major new release).

-- 
Joseph S. Myers
joseph@codesourcery.com