usb: storage: scsiglue: Do not skip VPD if try_vpd_pages is set

If BLIST_TRY_VPD_PAGES is set for a device, even for an USB, it should
be honored, so only set skip_vpd_pages is try_vpd_pages is not set.

Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>