Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2015-02-26' into staging

QemuOpts: Convert various setters to Error

# gpg: Signature made Thu Feb 26 13:56:43 2015 GMT 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-error-2015-02-26:
  qtest: Use qemu_opt_set() instead of qemu_opts_parse()
  pc: Use qemu_opt_set() instead of qemu_opts_parse()
  qemu-sockets: Simplify setting numeric and boolean options
  block: Simplify setting numeric options
  qemu-img: Suppress unhelpful extra errors in convert, amend
  QemuOpts: Propagate errors through opts_parse()
  QemuOpts: Propagate errors through opts_do_parse()
  QemuOpts: Drop qemu_opt_set(), rename qemu_opt_set_err(), fix use
  block: Suppress unhelpful extra errors in bdrv_img_create()
  qemu-img: Suppress unhelpful extra errors in convert, resize
  QemuOpts: Convert qemu_opts_set() to Error, fix its use
  QemuOpts: Convert qemu_opt_set_number() to Error, fix its use
  QemuOpts: Convert qemu_opt_set_bool() to Error, fix its use

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