MB-100: Remove unused cursorExists function

Change-Id: Ifb1b03594f034a13688f94726538a5b651b4d3bc
Reviewed-on: http://review.couchbase.org/29111
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Tested-by: Chiyoung Seo <chiyoung.seo@gmail.com>
MB-9123: Add checkpoint tests back to the Makefile

Since we will be making a bunch of changes to the checkpoint
manager in the near future adding thes back will help make it
easier to add new tests.

Change-Id: I64036319633e4c5a8ecab82d04f3962e121de68b