Merge remote-tracking branch 'remotes/famz/tags/staging-pull-request' into staging

Block patches 2018-03-01

Coverity fixes for nvme://

# gpg: Signature made Thu 01 Mar 2018 07:24:24 GMT
# gpg:                using RSA key CA35624C6A9171C6
# gpg: Good signature from "Fam Zheng <famz@redhat.com>"
# Primary key fingerprint: 5003 7CB7 9706 0F76 F021  AD56 CA35 624C 6A91 71C6

* remotes/famz/tags/staging-pull-request:
  block/nvme: fix Coverity reports

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>