Expand the scope of transaction in the process of deleting device
Expand the scope of transaction in the process of deleting device

When "docker load $image" and "docker rmi $image" commands are
repeatedly executed in the background, the dockerd daemon process is
killed. As a result, the DM device where the image resides may be
unavailable. The image can be queried, but the container fails to be
run. After function “devices.issueDiscard(info)” is executed and before
function "devices.deleteTransaction(info, syncDelete)" is executed, at
this point, dockerd daemon's withdrawal would result in dm device
discarded. Howerver, the dm device is not deleted at the same time.

Signed-off-by: gaohuatao <86377a537d75dedc160b96661fa0389dcc261c89@huawei.com>

rhatdan/storage,rhatdan/storage,containers/storage,rhatdan/storage,containers/storage,containers/storage