Avoid renaming data directory during MSVC upgrade testing.

This appears to cause some intermittent file system problems
on Windows 8. Instead, set up the old data directory in its
intended final location to start with.

src/tools/msvc/vcregress.pl

@@ -257,7 +257,7 @@ sub upgradecheck
 	  ("$tmp_install/bin", "$tmp_install/lib", $topdir, $topdir);
 	$ENV{PATH} = "$bindir;$ENV{PATH}";
 	my $data = "$tmp_root/data";
-	$ENV{PGDATA} = $data;
+	$ENV{PGDATA} = "$data.old";
 	my $logdir = "$topdir/contrib/pg_upgrade/log";
 	(mkdir $logdir || die $!) unless -d $logdir;
 	print "\nRunning initdb on old cluster\n\n";
@@ -272,10 +272,7 @@ sub upgradecheck
 	system("pg_dumpall -f $tmp_root/dump1.sql") == 0 or exit 1;
 	print "\nStopping old cluster\n\n";
 	system("pg_ctl -m fast stop") == 0 or exit 1;
-	rename $data, "$data.old";
-	# take a breather in case Windows hasn't quite got
-	# the message about the directory moving
-	sleep(5);
+	$ENV{PGDATA} = "$data";
 	print "\nSetting up new cluster\n\n";
 	system("initdb") == 0 or exit 1;
 	print "\nRunning pg_upgrade\n\n";