[Resource encapsulation]Add check logic about whether cached resource exists or not.

[Resource encapsulation]Add check logic about whether cached resource exists or not.

Throw exception when getCachedData() is requested for non-cached resource.
Add interface for checking cached resource existence.
Mutex for attributes is moved into the class member variable.

Change-Id: I25a163bf6900dd23f14158f28808873059798845
Signed-off-by: jyong2.kim <jyong2.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2024
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>