Make OpenAFS 1.6.21.1

Make OpenAFS 1.6.21.1

Update configure version strings for 1.6.21.1. Note that macos kext
can be of form XXXX.YY[.ZZ[(d|a|b|fc)NNN]] where d dev, a alpha,
b beta, f final candidate so we have no way to represent 1.6.21.1.
Switch to 1.6.22 dev 1 for macOs.

Change-Id: I73ebd481fdfe0d096b67138d4cb0f7b0d53e9e59
Reviewed-on: https://gerrit.openafs.org/12713
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>