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

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

* NBD fixes from Alex and Eric
* Debug code bitrot from Emilio
* HPET fix from Bill
* ps2kbd fix from Hervé
* PKU fix from myself
* Coverity fixes from Gonglei
* More memory.txt update from Jiangang
* .gitignore maintenance from Changlong

# gpg: Signature made Thu 07 Apr 2016 23:08:12 BST using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"

* remotes/bonzini/tags/for-upstream:
  target-i386: check for PKU even for non-writable pages
  tests: ignore test-logging
  translate-all: add missing fold of tb_ctx into tcg_ctx
  hostmem-file: fix memory leak
  spapr: fix possible Negative array index read
  nbd: do not hang nbd_wr_syncv if outside a coroutine and no available data
  nbd: Don't kill server when client requests unknown option
  nbd: Fix NBD unsupported options
  qemu-nbd: Document -x option
  nbd: Improve debug traces on little-endian
  nbd: Avoid bitrot in TRACE() usage
  nbd: Return correct error for write to read-only export
  docs: fix typo in memory.txt
  hw/timer: Revert "hpet: inverse polarity when pin above ISA_NUM_IRQS"
  ps2kbd: default to scancode_set 2, as with KBD_CMD_RESET

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