Rename Size_ to Size

Previouslty "Size" was reserved by protoc-gen-gogoctrd and user-generated
"Size" was automatically renamed to "Size_" to avoid conflicts.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

services/snapshots/service.go

@@ -300,7 +300,7 @@ func fromInfo(info snapshots.Info) *snapshotsapi.Info {
 func fromUsage(usage snapshots.Usage) *snapshotsapi.UsageResponse {
 	return &snapshotsapi.UsageResponse{
 		Inodes: usage.Inodes,
-		Size_:  usage.Size,
+		Size:   usage.Size,
 	}
 }