Resetting locals to undefined triggers a setter with an (undefined)record argument

[agonbina]

... the setter then tries to access attributes in the passed in record which ends up in throwing an exception.
https://github.com/js-data/js-data/blob/master/src/DataStore.js#L442, which triggers a setter(this block: https://github.com/js-data/js-data/blob/master/src/DataStore.js#L598-L630) with an undefined value, so this line here throws: https://github.com/js-data/js-data/blob/master/src/DataStore.js#L604 because record is undefined ...
Replacing utils.set(https://github.com/js-data/js-data/blob/master/src/DataStore.js#L442) with safeSet fixes the issue.