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

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

* --help/--version improvements (Eric)
* GCC 7 workaround (Greg)
* Small SCSI fix (Hannes)
* SSE 4.1 fix (Joseph)
* RCU deadlock fix (myself)

# gpg: Signature made Tue 08 Aug 2017 16:28:56 BST
# gpg:                using RSA key 0xBFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  maint: Include bug-reporting info in --help output
  qga: Give more --version information
  qemu-io: Give more --version information
  qemu-img: Sort sub-command names in --help
  target/i386: set rip_offset for some SSE4.1 instructions
  scsi: clarify sense codes for LUN0 emulation
  kvm: workaround build break on gcc-7.1.1 / fedora26
  Revert "rcu: do not create thread in pthread_atfork callback"
  rcu: completely disable pthread_atfork callbacks as soon as possible

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