Fix default persistent file location
Fix default persistent file location

This closes #146

purplecabbage/cordova-plugin-file,apache/cordova-plugin-file,sanmeranam/cordova-file,purplecabbage/cordova-plugin-file,mnill/cordova-plugin-file,GenusAS/cordova-plugin-file,purplecabbage/cordova-plugin-file,GenusAS/cordova-plugin-file,macdonst/cordova-plugin-file,cadenasgmbh/cordova-plugin-file,tripodsan/cordova-plugin-file,mnill/cordova-plugin-file,mnill/cordova-plugin-file,tripodsan/cordova-plugin-file,purplecabbage/cordova-plugin-file,GenusAS/cordova-plugin-file,starquake/cordova-plugin-file,starquake/cordova-plugin-file,cadenasgmbh/cordova-plugin-file,tripodsan/cordova-plugin-file,GenusAS/cordova-plugin-file,macdonst/cordova-plugin-file,cadenasgmbh/cordova-plugin-file,apache/cordova-plugin-file,sanmeranam/cordova-file,macdonst/cordova-plugin-file,mnill/cordova-plugin-file,cadenasgmbh/cordova-plugin-file,sanmeranam/cordova-file,tripodsan/cordova-plugin-file,sanmeranam/cordova-file,macdonst/cordova-plugin-file