Follow-up fix : Bug #18145121 - DEPRECATED PERL SYNTAX IN MTR

(cherry picked from commit 1bfe5f724bc4c24da635f632247e7d263aa53970)

Conflicts:
	mysql-test/lib/mtr_cases.pm

mysql-test/lib/mtr_cases.pm

 # -*- cperl -*-
-# Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
 # 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -336,7 +336,7 @@ sub collect_one_suite($)
   # Build a hash of disabled testcases for this suite
   # ----------------------------------------------------------------------
   my %disabled;
-  my @disabled_collection= @{$opt_skip_test_list} if defined @{$opt_skip_test_list};
+  my @disabled_collection= @{$opt_skip_test_list} if $opt_skip_test_list;
   unshift (@disabled_collection, "$testdir/disabled.def");
   for my $skip (@disabled_collection)
     {