[SPARK-4333][SQL] Correctly log number of iterations in RuleExecutor

When iterator of RuleExecutor breaks, the num of iterator should be (iteration - 1) not (iteration ).Because log looks like "Fixed point reached for batch ${batch.name} after 3 iterations.", but it did 2 iterations really!

Author: DoingDone9 <799203320@qq.com>

Closes apache#3180 from DoingDone9/issue_01 and squashes the following commits:

571e2ed [DoingDone9] Update RuleExecutor.scala
46514b6 [DoingDone9] When iterator of RuleExecutor breaks, the num of iterator should be iteration - 1 not iteration.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/rules/RuleExecutor.scala

@@ -79,7 +79,8 @@ abstract class RuleExecutor[TreeType <: TreeNode[_]] extends Logging {
         }
 
         if (curPlan.fastEquals(lastPlan)) {
-          logTrace(s"Fixed point reached for batch ${batch.name} after $iteration iterations.")
+          logTrace(
+            s"Fixed point reached for batch ${batch.name} after ${iteration - 1} iterations.")
           continue = false
         }
         lastPlan = curPlan