pg_upgrade: Add missing newline in output

This came from the backport of commit f295494d33, but older branches
require the explicit newline in messages (see commit 7652353d87).

src/bin/pg_upgrade/check.c

@@ -1302,7 +1302,7 @@ check_for_not_null_inheritance(ClusterInfo *cluster)
 	if (script)
 	{
 		fclose(script);
-		pg_log(PG_REPORT, "fatal");
+		pg_log(PG_REPORT, "fatal\n");
 		pg_fatal("Your installation contains inconsistent NOT NULL constraints.\n"
 				 "If the parent column(s) are NOT NULL, then the child column must\n"
 				 "also be marked NOT NULL, or the upgrade will fail.\n"