Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2015-09-04' into staging

qapi: Another round of fixes and cleanups

# gpg: Signature made Fri 04 Sep 2015 14:48:54 BST using RSA key ID EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"

* remotes/armbru/tags/pull-qapi-2015-09-04: (33 commits)
  qapi: Generators crash when --output-dir isn't given, fix
  docs/qapi-code-gen.txt: Fix QAPI schema examples
  qapi: Simplify error reporting for array types
  qapi: Fix errors for non-string, non-dictionary members
  tests/qapi-schema: Cover non-string, non-dictionary members
  tests/qapi-schema: Cover two more syntax errors
  qapi: Drop one of two "simple union must not have base" checks
  qapi: Generated code cleanup
  qapi-commands: Drop useless initialization
  qapi-commands: Don't feed output of mcgen() to mcgen() again
  qapi-commands: Inline gen_marshal_output_call()
  qapi-commands: Fix gen_err_check(e) for e and e != 'local_err'
  qapi: Command returning anonymous type doesn't work, outlaw
  qapi: Fix to reject union command and event arguments
  qapi-tests: New tests for union, alternate command arguments
  tests/qapi-schema: Rename tests from data- to args-
  tests/qapi-schema: Restore test case for flat union base bug
  qapi: Document flaws in checking of names
  qapi: Document shortcoming with union 'data' branch
  qapi: Document that input visitor semantics are prone to leaks
  ...

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