Merge remote-tracking branch 'mreitz/tags/pull-block-2017-04-28' into queue-block

Block patches for the block queue

# gpg: Signature made Fri Apr 28 20:50:48 2017 CEST
# gpg:                using RSA key 0xF407DB0061D5CF40
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>"
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* mreitz/tags/pull-block-2017-04-28:
  progress: Show current progress on SIGINFO
  iotests: fix exclusion option
  iotests: clarify help text
  qemu-img: use blk_co_pwrite_zeroes for zero sectors when compressed
  qemu-img: improve convert_iteration_sectors()
  block: assert no image modification under BDRV_O_INACTIVE
  block: fix obvious coding style mistakes in block_int.h
  qcow2: Allow discard of final unaligned cluster
  block: Add .bdrv_truncate() error messages
  block: Add errp to BD.bdrv_truncate()
  block: Add errp to b{lk,drv}_truncate()
  block/vhdx: Make vhdx_create() always set errp

Signed-off-by: Kevin Wolf <kwolf@redhat.com>