pgsql: Use the catversion to distinguish old/new clusters

Use the catversion to distinguish old/new clusters

This makes 9.3 -> 9.3 upgrades work when they cross the commit that
added persistent multixacts; early 9.3 pg_controldata did not have the
required oldestMultiXact line, and so would fail to upgrade.

per Bruce Momjian

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/34da700405737be055d1b3d310af23a98da72e8e

Modified Files
--------------
contrib/pg_upgrade/controldata.c |    4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)