optimize a print in

Signed-off-by: Yanqiang Miao <miao.yanqiang@zte.com.cn>

update 'optimize-a-print'

Signed-off-by: Yanqiang Miao <miao.yanqiang@zte.com.cn>

volume/volume.go

@@ -154,7 +154,7 @@ func (m *MountPoint) Type() string {
 // ParseVolumesFrom ensures that the supplied volumes-from is valid.
 func ParseVolumesFrom(spec string) (string, string, error) {
 	if len(spec) == 0 {
-		return "", "", fmt.Errorf("malformed volumes-from specification: %s", spec)
+		return "", "", fmt.Errorf("volumes-from specification cannot be an empty string")
 	}
 
 	specParts := strings.SplitN(spec, ":", 2)