let's reuse storeURLWithName method in the AGBaseStorage to return the calculate path and remove this
 
See:
  [https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGear-iOS/datamanager/AGBaseStorage.m#L25]
and
https://github.com/aerogear/aerogear-ios/blob/master/AeroGear-iOS/AeroGear-iOS/datamanager/AGPropertyListStorage.m#L56