CBLT-42:  fix more DOS typos, simplify setting REPO_SHA

Change-Id: I9b81b0cdcf3749af22a0b0b0a61126a94390a302
Reviewed-on: http://review.couchbase.org/37199
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>