Zombie record when id query mismatch

If I query for a record of id `1` and the server returns a record of id
`2` the store will have records of id `1` and id `2` as Ember Data
pre-emptively instantiates the record you are querying for.

A common use-case where this occurs is when querying for records with
a slug for an id. If I have a slug library server side for a Rails
application I do not want to just map my id column for the slug because
all of the relationships and foreign keys in my database are using the
auto-incrementing id column, not the slugs. The slugs are there for
presentation purposes only. However, on the client I will sometimes only
have a slug as the unique identifier to search for a given record on the
server.

This PR will do the following:

If you query the server for id `1` and it returns a record of id `2` it
will delete the previously instantiated record of id `1`.

If you already have a pre-existing record of id `1` that is committed
and query the server for id `1` and the server returns a record of id
`2` it will **not** delete the record of id `1`.