Retry errors which indicate the connection closed prematurely.

See discussion in #442

amazonclouddrive/amazonclouddrive.go

@@ -142,9 +142,6 @@ var retryErrorCodes = []int{
 // shouldRetry returns a boolean as to whether this resp and err
 // deserve to be retried.  It returns the err as a convenience
 func shouldRetry(resp *http.Response, err error) (bool, error) {
-	if err == io.EOF {
-		return true, err
-	}
 	return fs.ShouldRetry(err) || fs.ShouldRetryHTTP(resp, retryErrorCodes), err
 }