qmp: Fix BlockdevOptionQuorum.

Fix some nits before QEMU 2.0 freeze.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qmp: Make Quorum error events more palatable.

Insert quorum QMP events documentation alphabetically.

Also change the "ret" errno value by an optional "error" being an strerror(-ret)
in the QUORUM_REPORT_BAD qmp event.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qemu-io-test: Disable Quorum test when not compiled in.

Quorum is not compiled by default: make the quorum 081 test aware of this.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>