MB-10817: Don't bundle a copy of JSON_checker

Change-Id: Id832a887f22eacc56ec0f61fa97c7649fb68de8c
Reviewed-on: http://review.couchbase.org/35546
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>