[Systeminfo] Fixed behaviour of Network property

[Systeminfo] Fixed behaviour of Network property

[Bug] When using device with not supported feature
http://tizen.org/feature/network.telephony
e.g. R800 device, below code returns no error:
  tizen.systeminfo.getPropertyValueArray("NETWORK", (s) => {console.log(s)}, (s) => {console.log(s)})
listener for "NETWORK" property is never triggered also:
  tizen.systeminfo.addPropertyValueChangeListener("NETWORK", (s) => console.log(s));

[verification]
Systeminfo TCT 100% passrate.
After fix, listener and getter works properly on TW3.

Change-Id: I9f0d533055926d186305fb7c39418de1fed76f5b