Merge remote-tracking branch 'qmp/queue/qmp' into staging

* qmp/queue/qmp:
  qapi: fix qmp_balloon() conversion
  qemu-iotests: add block-stream speed value test case
  block: add 'speed' optional parameter to block-stream
  block: change block-job-set-speed argument from 'value' to 'speed'
  block: use Error mechanism instead of -errno for block_job_set_speed()
  block: use Error mechanism instead of -errno for block_job_create()