MB-12251: Throw error when only `start_range` or `end_range` is given

You need to supply both, `start_range` and `end_range` if you supply it
at all.

Change-Id: I62ffb4557124510d076bc3fefc3f5461f5843a49
Reviewed-on: http://review.couchbase.org/42760
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>