expanding the coverage of testing RCSResourceObject.cpp

expanding the coverage of testing RCSResourceObject.cpp

It calls both
addAttributeUpdatedListener(const std::string& key,AttributeUpdatedListener h)
addAttributeUpdatedListener(const std::string&& key,AttributeUpdatedListener h)

Change-Id: Ic46f85104fb4887515af9745b3dc11b3d90b9516
Signed-off-by: Rami Jung <rami.jung@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1938
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Hun-je Yeon <hunje.yeon@samsung.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>