modify scene manager(remote) for exception handling

modify scene manager(remote) for exception handling

- add exception handling for callback null check
- add mutex for name of scenelist, scenecollection
- remove unused code

Change-Id: Ib2c1c260cc9efc8372393dd08331be435d2c5c7e
Signed-off-by: Minji Park <minjii.park@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5309
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>