[DEBUG](iOS) libARDiscovery: Test if NetService TXTRecordData is not nil
[DEBUG](iOS) libARDiscovery: Test if NetService TXTRecordData is not nil

Change-Id: Ibd4552458fceaaf0418c273c6f01439a43ca5fd9

Parrot-Developers/ARSDKBuildUtils,Parrot-Developers/ARSDKBuildUtils