LP#1374091: Redefine view to help PG make better plans

The metabib.record_attr_flat view previously pulled its data
through several other intermediate views.  While this improves
maintenance overhead, it ends up being an optimization fence
for certain data sets.  So, we pull the logic from the leaf
views up into the main view.  And, poof, 2 orders of magnitude
speedup on large data sets.

Signed-off-by: Mike Rylander <miker@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>
LP#1374091: Speed up metarecord version of unAPI mra call

The change to metabib.record_attr_flat in the previous commit caused
a regression in the plan used in unapi.mmr_mra.  This commit addresses
that by unrolling the mra view when used in context with metarecords,
which are shaped differently and require slightly different access
patterns.

Signed-off-by: Mike Rylander <mrylander@gmail.com>
Signed-off-by: Ben Shum <bshum@biblio.org>
LP#1374091: stamping upgrade script for speedier record_attr views

Signed-off-by: Ben Shum <bshum@biblio.org>