spelling corrections in readme files

Fix spelling errors in readme files.

Reviewed-on: http://gerrit.openafs.org/8876
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
(cherry picked from commit 4042667388406e540c8a6546031d514793ffc8c4)

Change-Id: Idd64293533af373c2b467049442231bb85b6d7db
Reviewed-on: http://gerrit.openafs.org/9511
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>