Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

# gpg: Signature made Fri 26 Sep 2014 11:59:34 BST using RSA key ID 81AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

* remotes/stefanha/tags/tracing-pull-request:
  ohci: drop computed flags from trace events
  ohci: Split long traces to smaller ones
  scripts/tracetool: don't barf on formats with precision
  trace: install trace-events file
  trace-events: Fix comments pointing to source files
  trace-events: Drop orphaned monitor trace event
  trace-events: Drop unused megasas trace event
  cleanup-trace-events.pl: Tighten search for trace event call
  trace: tighten up trace-events regex to fix bad parse
  trace-events: drop orphan iscsi trace events
  trace-events: drop orphan usb_mtp_data_out
  trace-events: drop orphan virtio_blk_data_plane_complete_request
  trace: [hmp] Reimplement "trace-event" and "info trace-events" using QMP
  trace: [qmp] Add commands to query and control event tracing state
  trace: docs: add trace file description
  trace: [ust] Fix format string computation in tcg-enabled events

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