modify service combination

1. move the generated scripts to yeti directory
2. print the information when the scripts is generated successfully
3. when service option is absent, adjust the output format

Change-Id: I780b5e357283beaae3f1a9071418146fbbd91c56
Signed-off-by: Zhu Fangfang <fzhu@rbcon.com>
Reviewed-on: http://reviews.cloudfoundry.org/12893
Tested-by: CI Master <cf-ci@rbcon.com>
Reviewed-by: Pin Xie <pxie@vmware.com>