Merge remote-tracking branch 'remotes/kraxel/tags/usb-20181214-pull-request' into...

usb: fixes for mtp, ehci, usb-host and pvusb (xen).

# gpg: Signature made Fri 14 Dec 2018 10:38:33 GMT
# gpg:                using RSA key 4CB6D8EED3E87138
# 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>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/usb-20181214-pull-request:
  usb-mtp: Limit filename to object information size
  usb-mtp: use O_NOFOLLOW and O_CLOEXEC.
  ehci: fix fetch qtd race
  usb-host: reset and close libusb_device_handle before qemu exit
  pvusb: set max grants only in initialise

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