Commit 5f76a7aa is looking harmless from
the first glance, but it has changed things a lot. 'libvirt' uses it to
detect that it should follow new initialization way and this changes
things considerably. With this procedure followed, blockdev_init() is
not called anymore and thus block_acct_setup() helper is not called.

This means in particular that defaults for block accounting statistics
are changed and account_invalid/account_failed are actually initialized
as false instead of true originally.

This commit changes things to match original world. There are the following
constraints:
* new default value in block_acct_init() is set to true
* block_acct_setup() inside blockdev_init() is called before
  blkconf_apply_backend_options()
* thus newly created option in block device properties has precedence if
  specified

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
CC: Peter Krempa <pkrempa@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: John Snow <jsnow@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220824095044.166009-3-den@openvz.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>