[IOT-2895] Make DevConf resource non-observable.
[IOT-2895] Make DevConf resource non-observable.

Required to make the successful execution of the CTT test case
which expects observe notification from DevConf.
As DevConf is a read-only resource, it is not possible to update its
properties and hence there can't be any observe notifications.
So this change makes DevConf non-observable.

Change-Id: I8c73865aa995a61729e41063dfa0a74d0bea1400
Signed-off-by: Senthil Kumar G S <0add671b5ee96afb9c3e97fcabc956a9e39ac5ac@samsung.com>

iotivity/iotivity,rzr/iotivity,iotivity/iotivity,iotivity/iotivity,rzr/iotivity,iotivity/iotivity,rzr/iotivity,iotivity/iotivity,rzr/iotivity,iotivity/iotivity,rzr/iotivity,rzr/iotivity,rzr/iotivity,iotivity/iotivity,iotivity/iotivity