修改异常信息

git-svn-id: http://code.alibabatech.com/svn/dubbo/trunk@647 1a56cb94-b969-4eaa-88fa-be21384802f2

dubbo-common/src/main/java/com/alibaba/dubbo/common/utils/StringUtils.java

@@ -148,7 +148,7 @@ public final class StringUtils
         PrintWriter p = new PrintWriter(w);
         p.print(e.getClass().getName());
         if (e.getMessage() != null) {
-            p.print(e.getMessage());
+            p.print(": " + e.getMessage());
         }
         p.println();
         try {