add deregister of observe and delete subscription list from observeid

add deregister of observe and delete subscription list from observeid

this commit included
add DeleteSubDatafromObid function in NSProviderMemoyCache.
this function is deleted from the subscription list of same observe id.
The function will be called when an observe deregister is requested.
fourth patch included add mutex unlock.

Change-Id: I47810fea34e95e1da789b5ef36ff04aa6c5bd956
Signed-off-by: jaesick.shin <jaesick.shin@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/9513
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>