bitmaps: remove x- prefix from QMP api

Fix some outstanding bugs, change the design of an API element, remove the x- prefix to signify stability, and add iotests.

V6:
- Cover letter touchups
- 09: Rewrite qmp_filter to cope with lists or dicts.
- 11: small touchups.

V5:

002: New bugfix.
003: I forgot to actually capture state->bitmap anywhere,
which is needed for restoration...
007: Better commit message
- use .items() instead of .keys() to save a lookup [Vladimir]
- use a sequence of tuples to preserve ordering in the OrderedDict constructor [Vladimir]
- Move the sort_keys boolean up from patch 010
008: Better commit message
009: Better commit message
010: Moved the sort_keys function up to patch 007
011: Expanded this test considerably:
- query_bitmaps can now show empty results,
and prefixes results with "bitmaps:" in the log
- logging declarations are one line [Vladimir]
- Added a bad version of the bitmap handoff transaction [Eric]
- Added a bad version of the bitmap merge transaction, which revealed a problem that patch 02 now addresses [Eric]
- Added bitmap removal / cleanup [Eric]
- Added newline at end of file. [Eric]

V4:
- Removed patches 1-5 which have been staged
- Rewrite qmp_log entirely, split into three patches
- Pretty-printing has been extended to log() as well as qmp_log()
- Adjust iotest 236 to be format generic instead of qcow2 [Vladimir]
- Adjust iotest 236 to not reduplicate serialization work [Vladimir]
- Many other small touchups

V3:
- Reworked qmp_log to pretty-print the outgoing command, too [Vladimir]
- Modified test to log only bitmap information [Vladimir]
- Test disable/enable transaction toggle [Eric]

John Snow (11):
blockdev: abort transactions in reverse order block/dirty-bitmap: remove assertion from restore
blockdev: n-ary bitmap merge
block: remove 'x' prefix from experimental bitmap APIs iotests.py: don't abort if IMGKEYSECRET is undefined
iotests: add filter_generated_node_ids
iotests: add qmp recursive sorting function
iotests: remove default filters from qmp_log
iotests: change qmp_log filters to expect QMP objects only
iotests: implement pretty-print for log and qmp_log
iotests: add iotest 236 for testing bitmap merge

 block/dirty-bitmap.c          |   1 -
 blockdev.c                    | 107 +++++++----
 qapi/block-core.json          |  56 +++---
 qapi/transaction.json         |  12 +-
 tests/qemu-iotests/206        |   8 +-
 tests/qemu-iotests/223        |   4 +-
 tests/qemu-iotests/236        | 161 ++++++++++++++++
 tests/qemu-iotests/236.out    | 351 ++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/group      |   1 +
 tests/qemu-iotests/iotests.py |  64 ++++++-
 10 files changed, 677 insertions(+), 88 deletions(-)
 create mode 100755 tests/qemu-iotests/236
 create mode 100644 tests/qemu-iotests/236.out

2.17.2