test459: fix for parallel runs

- change warniing message to work better with varying filename
  length.
- adapt test output check to new formatting

Follow-up to 97ccc4479f77ba3191c6
Closes #12423
diff --git a/src/tool_parsecfg.c b/src/tool_parsecfg.c
index dcc164c..da48700 100644
--- a/src/tool_parsecfg.c
+++ b/src/tool_parsecfg.c
@@ -210,9 +210,9 @@
             break;
           default:
             warnf(operation->global, "%s:%d: warning: '%s' uses unquoted "
-                  "whitespace that may cause side-effects. Consider quoting "
-                  "the value with double quotes?",
-                  filename, lineno, option);
+                  "whitespace", filename, lineno, option);
+            warnf(operation->global, "This may cause side-effects. "
+                  "Consider using double quotes?");
           }
         }
         if(!*param)
diff --git a/tests/data/test459 b/tests/data/test459
index 9fe135f..e46d029 100644
--- a/tests/data/test459
+++ b/tests/data/test459
@@ -56,8 +56,8 @@
 arg
 </protocol>
 <stderr mode="text">
-Warning: log/config:1: warning: 'data' uses unquoted whitespace that may cause 
-Warning: side-effects. Consider quoting the value with double quotes?
+Warning: %LOGDIR/config:1: warning: 'data' uses unquoted whitespace
+Warning: This may cause side-effects. Consider using double quotes?
 </stderr>
 </verify>
 </testcase>