polish: remove redundant cid Defined check

Author: frrist

arc_cache.go

@@ -127,11 +127,6 @@ func (b *arccache) View(k cid.Cid, callback func([]byte) error) error {
 		return callback(blk.RawData())
 	}
 
-	if !k.Defined() {
-		log.Error("undefined cid in arc cache")
-		return ErrNotFound
-	}
-
 	if has, _, ok := b.queryCache(k); ok && !has {
 		// short circuit if the cache deterministically tells us the item
 		// doesn't exist.
@@ -145,11 +140,6 @@ func (b *arccache) View(k cid.Cid, callback func([]byte) error) error {
 }
 
 func (b *arccache) Get(k cid.Cid) (blocks.Block, error) {
-	if !k.Defined() {
-		log.Error("undefined cid in arc cache")
-		return nil, ErrNotFound
-	}
-
 	if has, _, ok := b.queryCache(k); ok && !has {
 		return nil, ErrNotFound
 	}