Treat all remotedocumentadapter-command results as cancel in the case we

are canceling the command.

Before it could happen that we have a pending cancel on a layout command
but the layout command finishes normally. This enqueued a new write
command before the PrintActivity is notified. This in turn prevented the
printactivity from finishing as the write command was still pending.

Bug: 27642724
Change-Id: I3c532d53b0c66c40d2e48ab8b4419251ff473a79