CBLT-179:  replace curl commands with: CURL_CMD="curl --fail --retry 5"

Change-Id: Ib956bb5e7fa2a25d7c0548de0d10808853293065
Reviewed-on: http://review.couchbase.org/36530
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>