cloud: SConscript cleanup.

cloud: SConscript cleanup.

Removing settings already present in the global "env" variable
along with any modifications to that global environment to get rid
of cross dependencies between scripts and forcing them to be executed
in a specific order.

Bug: https://jira.iotivity.org/browse/IOT-1583
Change-Id: I27edcf846d9436636a61cd83852335f86133bb4a
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/21289
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-by: Mats Wichmann <mats@linux.com>
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>