Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2019-09-28' into staging

Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2019-09-28' into staging

QAPI patches for 2019-09-28

# gpg: Signature made Sat 28 Sep 2019 16:18:13 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2019-09-28: (27 commits)
  qapi: Improve source file read error handling
  qapi: Improve reporting of redefinition
  qapi: Improve reporting of missing documentation comment
  qapi: Eliminate check_keys(), rename check_known_keys()
  qapi: Improve reporting of invalid 'if' further
  qapi: Avoid redundant definition references in error messages
  qapi: Improve reporting of missing / unknown definition keys
  qapi: Improve reporting of invalid flags
  qapi: Improve reporting of invalid 'if' errors
  qapi: Move context-free checking to the proper place
  qapi: Move context-sensitive checking to the proper place
  qapi: Inline check_name() into check_union()
  qapi: Plumb info to the QAPISchemaMember
  qapi: Make check_type()'s array case a bit more obvious
  qapi: Move check for reserved names out of add_name()
  qapi: Report invalid '*' prefix like any other invalid name
  qapi: Use check_name_str() where it suffices
  qapi: Improve reporting of invalid name errors
  qapi: Reorder check_FOO() parameters for consistency
  qapi: Improve reporting of member name clashes
  ...

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