Update upsert.js

this.record = this.loadOrInitializeRecord();

this.loadOrInitializeRecord is returning nothing therefore when assigning it to this.record, the record becomes undefined. 

I was having some issues creating a new record. Here is some testing code that I tried in chrome's javascript console.

var ret; function test(){}; ret = test(); 

ret
undefined

var ret; function test(){ret = 2}; ret = test(); 
ret
undefined


Cheers!!