added a convenience method.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@4777 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/util/StreamTaskListener.java

@@ -56,6 +56,10 @@ public final class StreamTaskListener implements TaskListener, Serializable {
         return new PrintWriter(new OutputStreamWriter(out),true);
     }
 
+    public void error(String format, Object... args) {
+        out.printf(format,args);
+    }
+
     public PrintWriter fatalError(String msg) {
         return error(msg);
     }