QAPI patches for 2017-05-04

# gpg: Signature made Tue 09 May 2017 03:16:12 AM EDT
# gpg:                using RSA key 0x3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* armbru/tags/pull-qapi-2017-05-04-v3: (28 commits)
  qmp-shell: improve help
  qmp-shell: don't show version greeting if unavailable
  qmp-shell: Cope with query-commands error
  qmp-shell: add -N option to skip negotiate
  qmp-shell: add persistent command history
  qobject-input-visitor: Catch misuse of end_struct vs. end_list
  qapi: Document intended use of @name within alternate visits
  qobject-input-visitor: Document full_name_nth()
  qmp: Improve QMP dispatch error messages
  sockets: Delete unused helper socket_address_crumple()
  sockets: Limit SocketAddressLegacy to external interfaces
  sockets: Rename SocketAddressFlat to SocketAddress
  sockets: Rename SocketAddress to SocketAddressLegacy
  qapi: New QAPI_CLONE_MEMBERS()
  sockets: Prepare inet_parse() for flattened SocketAddress
  sockets: Prepare vsock_parse() for flattened SocketAddress
  test-qga: Actually test 0xff sync bytes
  fdc-test: Avoid deprecated 'change' command
  QemuOpts: Simplify qemu_opts_to_qdict()
  block: Simplify bdrv_append_temp_snapshot() logic
  ...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>