s3: Remove cache

src/restic/backend/s3/s3.go

@@ -8,7 +8,6 @@ import (
 	"path"
 	"restic"
 	"strings"
-	"sync"
 	"time"
 
 	"restic/backend"
@@ -27,8 +26,6 @@ type s3 struct {
 	sem        *backend.Semaphore
 	bucketname string
 	prefix     string
-	cacheMutex   sync.RWMutex
-	cacheObjSize map[string]int64
 	backend.Layout
 }
 
@@ -57,7 +54,6 @@ func Open(cfg Config) (restic.Backend, error) {
 		sem:        sem,
 		bucketname: cfg.Bucket,
 		prefix:     cfg.Prefix,
-		cacheObjSize: make(map[string]int64),
 	}
 
 	client.SetCustomTransport(backend.Transport())