Merge remote-tracking branch 'remotes/kraxel/tags/pull-usb-20150320-1' into staging

usb: bugfix collection.

# gpg: Signature made Fri Mar 20 07:51:19 2015 GMT 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-usb-20150320-1:
  ehci: fix segfault when hot-unplugging ehci controller
  ohci: fix resource cleanup leak
  uhci: fix segfault when hot-unplugging uhci controller
  hw/usb: Include USB files only if necessary
  usb/dev-storage: Avoid qerror_report_err() outside QMP handlers
  usb/dev-storage: Fix QMP device_add missing encryption key failure
  monitor usb: Inline monitor_read_bdrv_key_start()'s first part
  monitor: Plug memory leak in monitor_read_bdrv_key_start()
  monitor: Drop dead QMP check from monitor_read_password()
  uhci: Convert to realize
  ohci: Complete conversion to realize
  usb: Improve companion configuration error messages
  usb: Propagate errors through usb_register_companion()

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