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

* Fix pr-manager-helper (Markus)

# gpg: Signature made Wed 05 Jun 2019 15:15:34 BST
# gpg:                using RSA key BFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  vl: Document why objects are delayed
  vl: Fix -drive / -blockdev persistent reservation management

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