pgsql: Fix some failures to initialize table entries induced by recent

Log Message:
-----------
Fix some failures to initialize table entries induced by recent autovacuum
integration. Not clear this explains recent stats problems, but it's
definitely wrong.

Modified Files:
--------------
pgsql/src/backend/postmaster:
pgstat.c (r1.100 -> r1.101)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/pgstat.c.diff?r1=1.100&r2=1.101)