USB: usb-storage: fix initializations of urb fields

Commit 0ede76fc, "USB: remove uses of
URB_NO_SETUP_DMA_MAP" introduced a regression by inadvertantly removing
initialization of the transfer flags.  This caused initialization
failures in the ums-karma driver.  Fix the regression by zeroing it.

While at it, as Alan Stern points out, the initializers for
actual_length and status are handled by the core and error_count
only matters for isochronous urbs, so they don't need to be set here.
Remove them.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>