yaml: Add scriptlet to clone before scons
yaml: Add scriptlet to clone before scons

Bug: https://jira.iotivity.org/browse/IOT-1760
Change-Id: Ief605d40b83d437df4049d18af7188eaea0ecbcb
Signed-off-by: Philippe Coval <ff46fec9739d31cce915aabcc3a7a2c00eee4d6c@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/21623
Tested-by: jenkins-iotivity <d95b56ce41a2e1ac4cecdd398defd7414407cc08@iotivity.org>
Reviewed-by: Dan Mihai <ba8e1833495515b49ded9e20cae80a8129155aa9@microsoft.com>
(cherry picked from commit 286bc151acf0e8f2b67932d0fca2405cc859375e)
Reviewed-on: https://gerrit.iotivity.org/gerrit/22079
Reviewed-by: Mats Wichmann <7a5e6f27299d2bbd9d04b59d9e8e4f8eab83d8cb@linux.com>

rzr/iotivity,iotivity/iotivity,iotivity/iotivity,iotivity/iotivity,rzr/iotivity,rzr/iotivity,iotivity/iotivity,iotivity/iotivity,rzr/iotivity,iotivity/iotivity,iotivity/iotivity,rzr/iotivity,rzr/iotivity,iotivity/iotivity,rzr/iotivity