Merge remote-tracking branch 'remotes/dgilbert/tags/pull-hmp-20190501' into staging

HMP pull

New gva2gpa command
delvm now uses hmp_handle_error so gets Error: prefix in messages

# gpg: Signature made Wed 01 May 2019 11:57:43 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-hmp-20190501:
  hmp: gva2gpa debug command
  hmp: delvm: use hmp_handle_error

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