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

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

* remotes/qmp-unstable/queue/qmp:
  json-parser: drop superfluous assignment for token variable
  readline: Clear screen on form feed.
  monitor: Add delvm and loadvm argument completion
  monitor: Add host_net_remove arguments completion
  readline: Make completion strings always unique
  monitor: Add host_net_add device argument completion
  net: Export valid host network devices list
  monitor: Add migrate_set_capability completion
  monitor: Add watchdog_action argument completion
  monitor: Add ringbuf_write and ringbuf_read argument completion
  dump: simplify get_len_buf_out()
  dump: hoist lzo_init() from get_len_buf_out() to dump_init()
  dump: select header bitness based on ELF class, not ELF architecture
  dump: eliminate DumpState.page_size ("guest's page size")
  dump: eliminate DumpState.page_shift ("guest's page shift")
  dump: simplify write_start_flat_header()
  dump: fill in the flat header signature more pleasingly to the eye

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