Reorder "Getting Started" sections

Put the ones most likely to be relevant at the top, instead
of sorting alphabetically.

Change-Id: I6ad80ee2a30b7192d8c8e4668234fa1789e1a213
Reviewed-on: http://gerrit.openafs.org/11576
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: D Brashear <shadow@your-file-system.com>