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

Block layer patches

# gpg: Signature made Fri 04 Sep 2015 20:45:33 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream:
  quorum: validate vote threshold against num_children even if read-pattern is fifo
  qcow2: reorder fields in Qcow2CachedTable to reduce padding
  docs: document how to configure the qcow2 L2/refcount caches
  qcow2: add option to clean unused cache entries after some time
  qcow2: mark the memory as no longer needed after qcow2_cache_empty()
  iotests: Warn if python subprocess is killed
  iotests: Do not suppress segfaults in bash tests
  iotests: Respect -nodefaults in tests 41 and 55
  iotests: More options for VM.add_drive()
  qemu-img: Fix crash in amend invocation
  block/raw-posix: Use raw_normalize_devicepath()
  qemu-iotests: s390x: fix test 130
  qemu-iotests: s390x: fix test 049, reject negative sizes in QemuOpts
  qemu-iotests: s390x: fix test 041 and 055
  qemu-iotests: disable default qemu devices for cross-platform compatibility
  qemu-iotests: qemu machine type support

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