Merge remote-tracking branch 'remotes/kraxel/tags/pull-chardev-2' into staging

purge error_is_set()

# gpg: Signature made Wed 21 May 2014 11:43:44 BST using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"

* remotes/kraxel/tags/pull-chardev-2:
  error: error_is_set() is finally unused; remove
  char: Explain qmp_chardev_add()'s unusual error handling
  char: Clean up fragile use of error_is_set()
  char: Use return values instead of error_is_set(errp)
  qemu-socket: Clean up inet_connect_opts()

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