Merge remote-tracking branch 'remotes/jnsnow/tags/bitmaps-pull-request' into staging

Merge remote-tracking branch 'remotes/jnsnow/tags/bitmaps-pull-request' into staging

Pull request

# gpg: Signature made Wed 16 Jan 2019 01:00:25 GMT
# gpg:                using RSA key 7DEF8106AAFC390E
# gpg: Good signature from "John Snow (John Huston) <jsnow@redhat.com>"
# Primary key fingerprint: FAEB 9711 A12C F475 812F  18F2 88A9 064D 1835 61EB
#      Subkey fingerprint: F9B7 ABDB BCAC DF95 BE76  CBD0 7DEF 8106 AAFC 390E

* remotes/jnsnow/tags/bitmaps-pull-request:
  Revert "hbitmap: Add @advance param to hbitmap_iter_next()"
  Revert "test-hbitmap: Add non-advancing iter_next tests"
  Revert "block/dirty-bitmap: Add bdrv_dirty_iter_next_area"
  block/mirror: fix and improve do_sync_target_write
  tests: add tests for hbitmap_next_dirty_area
  dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area
  tests: add tests for hbitmap_next_zero with specified end parameter
  dirty-bitmap: improve bdrv_dirty_bitmap_next_zero

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