Make code following the documentation.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@617470 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/TaskConfigurationChecker.java

@@ -75,7 +75,7 @@ public class TaskConfigurationChecker {
      * @param errormessage  errormessage to throw if a condition failed
      */
     public void assertConfig(boolean condition, String errormessage) {
-        if (condition) {
+        if (!condition) {
             errors.add(errormessage);
         }
     }