xen/blkback: Update to use blkdev_get_by_dev instead of open_by_devnum.

The API for opening a block device has changed since 2.6.32. The
correct function to open a device is blkdev_get_by_dev.
This commit is contained in:
Konrad Rzeszutek Wilk 2011-02-25 10:02:39 -05:00
commit bc0c081b0e