fixed some problems with the caching example
fixed some problems with the caching example

A-Manning/FStar,FStarLang/FStar,hoheinzollern/FStar,MallabaevAzamat/FStar,FStarLang/FStar,A-Manning/FStar,aa755/FStar,MallabaevAzamat/FStar,aa755/FStar,msprotz/FStar,MallabaevAzamat/FStar,msprotz/FStar,hoheinzollern/FStar,hoheinzollern/FStar,A-Manning/FStar,hoheinzollern/FStar,YaccConstructor/FStar,YaccConstructor/FStar,YaccConstructor/FStar,aa755/FStar,aa755/FStar,MallabaevAzamat/FStar,msprotz/FStar,msprotz/FStar,YaccConstructor/FStar,FStarLang/FStar