pgsql: When a bitmap indexscan is using a partial index, it is necessary

Log Message:
-----------
When a bitmap indexscan is using a partial index, it is necessary to include
the partial index predicate in the scan's "recheck condition".  Otherwise,
if the scan becomes lossy for lack of bitmap memory, we would fail to enforce
that returned rows satisfy the predicate.  Noted while studying bug #2441
from Arjen van der Meijden.

Modified Files:
--------------
    pgsql/src/backend/optimizer/plan:
        createplan.c (r1.210 -> r1.211)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/plan/createplan.c.diff?r1=1.210&r2=1.211)