Merge remote-tracking branch 'kwolf/tags/for-upstream' into staging

Block layer patches for 2.8.0-rc1

# gpg: Signature made Tue 22 Nov 2016 03:55:38 PM GMT
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* kwolf/tags/for-upstream:
  block: Pass unaligned discard requests to drivers
  block: Return -ENOTSUP rather than assert on unaligned discards
  block: Let write zeroes fallback work even with small max_transfer
  qcow2: Inform block layer about discard boundaries

Message-id: 1479830693-26676-1-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>