Fix LSN formatting in expected test message

Author: Sofia Kopikova

t/001_basic.pl

@@ -119,7 +119,7 @@ BEGIN
 my $init_lsn = $node->safe_psql("postgres", "SELECT ptrack_init_lsn()");
 like(
 	$init_lsn,
-	qr/0\/[0-9][0-9]+/,
+	qr/0\/[0-9A-F][0-9A-F]+/,
 	'ptrack init LSN should not be 0/0 after CHECKPOINT');
 
 # Ptrack map should survive crash
@@ -163,7 +163,7 @@ BEGIN
 $res_stdout = $node->safe_psql("postgres", "SELECT ptrack_init_lsn()");
 like(
 	$res_stdout,
-	qr/0\/[0-9][0-9]+/,
+	qr/0\/[0-9A-F][0-9A-F]+/,
 	'ptrack init LSN should not be 0/0 after CHECKPOINT');
 ok($res_stdout ne $init_lsn, 'ptrack init_lsn should not be the same after map resize');
 $res_stdout = $node->safe_psql("postgres", "SELECT ptrack_get_pagemapset('$flush_lsn')");