use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/golang/groupcache/lru/lru.go

@@ -25,7 +25,7 @@ type Cache struct {
 	// an item is evicted. Zero means no limit.
 	MaxEntries int
 
-	// OnEvicted optionally specifies a callback function to be
+	// OnEvicted optionally specificies a callback function to be
 	// executed when an entry is purged from the cache.
 	OnEvicted func(key Key, value interface{})
 
@@ -119,15 +119,3 @@ func (c *Cache) Len() int {
 	}
 	return c.ll.Len()
 }
-
-// Clear purges all stored items from the cache.
-func (c *Cache) Clear() {
-	if c.OnEvicted != nil {
-		for _, e := range c.cache {
-			kv := e.Value.(*entry)
-			c.OnEvicted(kv.key, kv.value)
-		}
-	}
-	c.ll = nil
-	c.cache = nil
-}