Pull xen block driver fixes from Jens Axboe:
"A few small bug fixes for xen-blk{front,back} that have been sitting
over my vacation"
* 'for-linus' of git://git.kernel.dk/linux-block:
xen-blkback: replace work_pending with work_busy in purge_persistent_gnt()
xen-blkfront: don't add indirect pages to list when !feature_persistent
xen-blkfront: introduce blkfront_gather_backend_features()