typo fix.

Author: yingjieMiao

core/src/main/scala/org/apache/spark/rdd/AsyncRDDActions.scala

@@ -82,11 +82,11 @@ class AsyncRDDActions[T: ClassTag](self: RDD[T]) extends Serializable with Loggi
           // Otherwise, interpolate the number of partitions we need to try, but overestimate it
           // by 50%. We also cap the estimation in the end.
           if (results.size == 0) {
-            numPartsToTry = totalParts * 4
+            numPartsToTry = partsScanned * 4
           } else {
             // the left side of max is >=1 whenever partsScanned >= 2
             numPartsToTry = ((1.5 * num * partsScanned / results.size).toInt - partsScanned) max 1
-            numPartsToTry = numPartsToTry min (totalParts * 4) 
+            numPartsToTry = numPartsToTry min (partsScanned * 4) 
           }
         }