[#4666] fixed BackOffSleepTask max waiting time to 10 minute (#4668)

Author: chengyouling

clients/http-client-common/src/main/java/org/apache/servicecomb/http/client/task/AbstractTask.java

@@ -30,7 +30,7 @@ public class AbstractTask {
   public class BackOffSleepTask implements Task {
     private static final long BASE = 3000;
 
-    private static final long MAX = 10 * 60 * 10000;
+    private static final long MAX = 10 * 60 * 1000;
 
     long waitTime;