Fix auto install with "storage_init=/dev/sda,/dev/sda" failed issue

Change-Id: I700200dc612c221fcb5a3ac663bbe8f7a5e77bfc
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=961706
Signed-off-by: hadong <hadong0720@gmail.com>