Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-12-20' into staging

QAPI patches for 2017-12-20

# gpg: Signature made Wed 20 Dec 2017 18:53:28 GMT
# gpg:                using RSA key 0x3870B400EB918653
# gpg: Good signature from "Markus Armbruster <[email protected]>"
# gpg:                 aka "Markus Armbruster <[email protected]>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2017-12-20:
  qmp: remove qmp_cpu
  qapi-docs: fix a comment typo
  qapi2texi: De-duplicate code to add blank line before symbol
  qapi: Rename QAPIDoc.parser, .section to ._parser, ._section
  qapi2texi: Simplify representation of section text
  qapi: Simplify representation of QAPIDoc section text
  qapi: Unify representation of doc section without name
  qapi2texi: Clean up texi_sections()
  tests/qapi-schema/doc-bad-section: New, factored out of doc-good
  qapi: Make cur_doc local to QAPISchemaParser.__init__()
  qapi: Eliminate QAPISchemaParser.__init__()'s local fname
  qapi: Stop rejecting #optional
  qapi-schema: Fix query-vm-generation-id's doc comment markup

Signed-off-by: Peter Maydell <[email protected]>