Fix test for ldap.search return codes

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Author: dzaporozhets

test/integration/test_return_codes.rb

@@ -29,7 +29,7 @@ def test_time_limit_exceeded
   end
 
   def test_size_limit_exceeded
-    refute @ldap.search(filter: "cn=sizeLimitExceeded", base: "ou=Retcodes,dc=rubyldap,dc=com")
+    assert @ldap.search(filter: "cn=sizeLimitExceeded", base: "ou=Retcodes,dc=rubyldap,dc=com")
     assert result = @ldap.get_operation_result
 
     assert_equal 4, result.code