regress: set default controller in failover

Set the controllers to the default values if no controllers are
specified. (Previous code would only set the controller to the defaults
if there was a problem parsing the command line options.)

regress/projects/black_box/regress/test_failover_startup/run.pl

@@ -26,10 +26,10 @@ my $controllers;
 
 # Remove '--controller' from the option list... - Jean II
 Getopt::Long::Configure( 'pass_through' );
-unless (
-    GetOptions(
-			"controller=s"		=> \$controllers
-    ) )
+GetOptions(
+		"controller=s"		=> \$controllers
+);
+if (!defined($controllers))
 {
     # If no controllers specified, use default
     $controllers = nftest_default_controllers();