tizen: Fixed RHSampleApp project file to use SDK path separator

tizen: Fixed RHSampleApp project file to use SDK path separator

This MSDOS '\' will break support on non Windows tizen-sdk

Change-Id: I83aaa2529d9d317a9f6406beba40ec6de8fddfcf
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/6147
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Mats Wichmann <mats@osg.samsung.com>
Reviewed-by: JungYong KIM <jyong2.kim@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5499