### Issue Description Can't use authData as Query-Parameter ### Steps to reproduce 1. Authenticate via an Authentication Adapter so authData is added to the User object. 2. Run a Query (with masterkey enabled) like GET API_BACKEND/classes/_User?where={"authData":{"$exists": true}} #### Expected Results Query Result should contain all Users with non empty authData fields #### Actual Outcome Query Result is empty ### Environment Setup - **Server** - parse-server version (Be specific! Don't say 'latest'.) : 2.4.2 - Operating System: ubuntu 16.10 - Hardware: VM - Localhost or remote server? (AWS, Heroku, Azure, Digital Ocean, etc): local