Fix bugs about memory free at Notification scheduler, and don't initialize observe...

Fix bugs about memory free at Notification scheduler, and don't initialize observe id in NSProviderSubscription.

This commit included bug fixed.
1. double freeing of memory int stopscheduler function.
2. The code has been cleared from the prevous commit.
   added initialize code of observeid.

second, third patch included
delete not required header and add required header.

Change-Id: I56b330ef99f6ef6b57c81afd0e75e25dfaf5306b
Signed-off-by: jaesick.shin <jaesick.shin@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/9605
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Tested-by: Uze Choi <uzchoi@samsung.com>