Change build script to require code signing only for load-device target.
Change build script to require code signing only for load-device target.

blackberry/cordova-blackberry,apache/cordova-blackberry,apache/cordova-blackberry,blackberry/cordova-blackberry,deedubbu/incubator-cordova-blackberry-webworks,corimf/cordova-blackberry,apache/cordova-blackberry,blackberry/cordova-blackberry,deedubbu/incubator-cordova-blackberry-webworks,corimf/cordova-blackberry,corimf/cordova-blackberry