pgsql: Only send cleanup_info messages if VACUUM removes any tuples.

Log Message:
-----------
Only send cleanup_info messages if VACUUM removes any tuples.
There is no other purpose for this message type than to report
the latestRemovedXid of removed tuples, prior to index scans.
Removes overlooked path for sending invalid latestRemovedXid.
Fixes buildfarm failure on centaur.

Modified Files:
--------------
    pgsql/src/backend/commands:
        vacuumlazy.c (r1.133 -> r1.134)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/vacuumlazy.c?r1=1.133&r2=1.134)