Fix deprecation warnings

Rewrite to fix these deprecation warnings:
```
Relation#first with finder options is deprecated
Relation#update_all with conditions is deprecated
```
@joneslee85, I've gotten past bundle not finding 'spree_core (~> 2.2.0.beta) ruby' but am now getting this trying to build the test app:
```
No such file or directory - /Users/james/dev/spree_wishlist/spec/dummy/app/assets/javascripts/store/all.js
```

Thoughts?