CBIT-532:  sync source to dir under: {WORKSPACE}/app-under-test
           use go-manifest script to compute manifest.txt

Change-Id: I6d7133d94f48d272867907bcc18eb07abe3bf452
Reviewed-on: http://review.couchbase.org/37776
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>