Fix storage items deletion after $reset call
Fix storage items deletion after $reset call

This fixes #48, a bug about not deleting items from the storage after
$reset being called.

cristianbara/ngStorage,egilkh/ngStorage,brennaman/ngStorage,BaggersIO/ngStorage,grantadesign/ngStorage,imskojs/ngStorage,williamboman/ngStorage,meghna1711/ngStorage,Arteaga2k/ngStorage,castle-it/ngStorage,linalu1/ngStorage,xxxkonyi/ngStorage,stefanita/ngStorage,robinboehm/ngStorage,gsklee/ngStorage,mhasan3/ngStorage,kknirala/ngStorage,4talesa/ngStorage,wyvern8/ngStorage,lalithr95/ngStorage,wodka/ngStorage,selimg/ngStorage,GerryFudd/ngStorage,prudvihemanth/ngStorage,rbecheras/ngStorage,JulienBier/ngStorage,bratishchev/ngStorage