service/simulator: SConscript cleanup

service/simulator: SConscript cleanup

This is a scons scripts cleanup left after fixing /W4 warnings for Windows.

Preparing SConscript files for removal of arbitrary global "env"
modifications in script files outside build_common/ directory.

Bug: https://jira.iotivity.org/browse/IOT-1583
Change-Id: I6f6e01d1c95b28637aba494feed2801670a7947f
Signed-off-by: Pawel Winogrodzki <pawelwi@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/19565
Reviewed-by: Mats Wichmann <mats@linux.com>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-by: George Nash <george.nash@intel.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: C.J. Collier <cjcollier@linuxfoundation.org>
(cherry picked from commit c8c8213b861b7400f66c03f4671db1bbf5b02f69)
Reviewed-on: https://gerrit.iotivity.org/gerrit/21109
Tested-by: Phil Coval <philippe.coval@osg.samsung.com>
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>