MB-100: rename read configs

Change-Id: Ieaab3cb8f8c4f5fe4f6918b878d2f32ff29893c9
Reviewed-on: http://review.couchbase.org/25562
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>