Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging

This pull request contains:
- a patch to add a vdc->reset() handler to virtio-9p
- a bunch of patches to fix various memory leaks (thanks to Li Qiang)
- some code cleanups for 9pfs

# gpg: Signature made Mon 17 Oct 2016 16:01:46 BST
# gpg:                using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg:                 aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* remotes/gkurz/tags/for-upstream:
  9pfs: fix memory leak in v9fs_write
  9pfs: fix memory leak in v9fs_link
  9pfs: fix memory leak in v9fs_xattrcreate
  9pfs: fix information leak in xattr read
  virtio-9p: add reset handler
  9pfs: only free completed request if not flushed
  9pfs: drop useless check in pdu_free()
  9pfs: use coroutine_fn annotation in hw/9pfs/9p.[ch]
  9pfs: use coroutine_fn annotation in hw/9pfs/co*.[ch]
  9pfs: fsdev: drop useless extern annotation for functions
  9pfs: fix potential host memory leak in v9fs_read
  9pfs: allocate space for guest originated empty strings

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