Use ReadFull when reading chunks for torrent

When generating a torrent, we need to get the SHA1 hash of each chunk of
the file. Because we stream the data for S3, Read doesn't always fill
the chunk buffer, so to fix this, we can use ReadFull.

torrent.go

@@ -28,10 +28,10 @@ func createTorrent(fileName string, f io.Reader, r *http.Request) ([]byte, error
 	}
 
 	for {
-		n, err := f.Read(chunk)
+		n, err := io.ReadFull(f, chunk)
 		if err == io.EOF {
 			break
-		} else if err != nil {
+		} else if err != nil && err != io.ErrUnexpectedEOF {
 			return []byte{}, err
 		}
 
@@ -58,7 +58,8 @@ func fileTorrentHandler(c web.C, w http.ResponseWriter, r *http.Request) {
 		oopsHandler(c, w, r, RespAUTO, "Corrupt metadata.")
 		return
 	} else if err != nil {
-		oopsHandler(c, w, r, RespAUTO, "Could not create torrent.")
+		oopsHandler(c, w, r, RespAUTO, err.Error())
+		return
 	}
 	defer f.Close()