fix: reword score section in the scheduling framework

keps/sig-scheduling/20180409-scheduling-framework.md

@@ -206,9 +206,12 @@ each node.
 the scheduler computes a final ranking of Nodes, and each score plugin receives
 scores given by the same plugin to all nodes in "normalize scoring" phase. 
 `NormalizeScore` is called once per plugin per scheduling cycle right after 
-"score" phase. After the "normalize scoring" phase, it will return a well defined
-range of integers `[0, 100]`, the scheduler will combine node scores from all 
-plugins according to the configured plugin weights.
+"score" phase.
+
+The output of a score plugin must be an integer in range of
+**[NodeScoreMin, NodeScoreMax]**. if not, the scheduling cycle is aborted.
+This is the output after running the optional NormalizeScore function of the
+plugin. If NormalizeScore is not provided, the output of Score must be in this range
 
 For example, suppose a plugin `BlinkingLightScorer` ranks Nodes based on how
 many blinking lights they have.
@@ -223,50 +226,19 @@ However, the maximum count of blinking lights may be small compared to
 `NodeScoreMax`. To fix this, `BlinkingLightScorer` should also implement `NormalizeScore`.
 
 ```go
-func (*BlinkingLightScorer) NormalizeScore(pc *PluginContext, _ *v1.Pod, scores NodeScoreList) *Status {
+func (*BlinkingLightScorer) NormalizeScore(pc *PluginContext, _ *v1.Pod, nodeScores NodeScoreList) *Status {
    highest := 0
-   for _, score := range scores {
-      highest = max(highest, score)
+   for _, nodeScore := range nodeScores {
+      highest = max(highest, nodeScore.Score)
    }
-   for node, score := range scores {
-      scores[node] = score*NodeScoreMax/highest
+   for i, nodeScore := range nodeScores {
+      nodeScores[i].Score = nodeScore.Score*NodeScoreMax/highest
    }
    return nil
 }
 ```
 
-If `NormalizeScore` returns an error, the scheduling cycle is aborted. The 
-scheduler would use a default normalize score strategy if the user does not
-provide one.
-
-```go
-func DefaultNormalizeScore(pc *PluginContext, scores NodeScoreList) {
-   minScore := math.MinInt
-   maxScore := math.MaxInt
-
-   for _, score := range scores {
-       if minScore > score {
-           minScore = score
-       }
-
-       if maxScore < score {
-           maxScore = score
-       }
-   }
-
-   diff := maxScore - minScore
-   if diff == 0 {
-       for i := range scores {
-           scores[i] = 0
-       }
-       return
-   }
-
-   for i, score := range scores {
-       scores[i] = 100 * (score-minScore) / diff
-   }
-}
-```
+If `NormalizeScore` returns an error, the scheduling cycle is aborted.
 
 **Note:** Plugins wishing to perform "pre-reserve" work should use the `NormalizeScore` in the
 scoring extension point.