IssueTracker

Component used: WorkManager
Version used: 1.0.0-alpha12
Devices/Android versions reproduced on: Pixel 2 Emulator

Canceling work that is deeper in the chain (by tag) seems to cancel the work correctly, but it get enqueued again incorrectly.

DownloadCommentsWorker:
```
override fun doWork(): Result {
    System.out.println("$this::class.java - Started")
    Thread.sleep(Random.nextLong(5000))
    System.out.println("$this::class.java - Done")
    return Result.success()
}
```

FinalWorker:
```
override fun doWork(): Result {
    System.out.println("ALL WORK COMPLETE")
    return Result.success()
}
```

```
WorkManager.getInstance()
.beginUniqueWork("unique", ExistingWorkPolicy.KEEP, OneTimeWorkRequestBuilder<DownloadCommentsWorker>().build())
.then(OneTimeWorkRequestBuilder<FinalWorker>().addTag("finally").build())
.enqueue()

WorkManager.getInstance().getWorkInfosForUniqueWorkLiveData("unique").observe(this, workInfos -> {
    for (WorkInfo info : workInfos) {
        System.out.println(info.toString());
    }
});

WorkManager.getInstance().cancelAllWorkByTag("finally").getState().observe(this, state -> {
    System.out.println(state);
});
```

Console Output
```
2018-12-11 11:04:51.182 6991-6991/com.plangrid.android.devgrid I/System.out: SUCCESS
2018-12-11 11:04:51.184 6991-7056/com.plangrid.android.devgrid I/System.out: com.plangrid.android.workmanager.DownloadCommentsWorker@e5d859f::class.java - Started
2018-12-11 11:04:51.240 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='4eac7884-3374-494a-a549-fcd7505fc5b4', mState=CANCELLED, mOutputData=androidx.work.Data@0, mTags=[finally, com.plangrid.android.workmanager.FinalWorker]}
2018-12-11 11:04:51.240 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='c8e75590-8f60-40b7-a2e6-4e7aa6e7830d', mState=RUNNING, mOutputData=androidx.work.Data@0, mTags=[com.plangrid.android.workmanager.DownloadCommentsWorker]}
2018-12-11 11:04:54.488 6991-7056/com.plangrid.android.devgrid I/System.out: com.plangrid.android.workmanager.DownloadCommentsWorker@e5d859f::class.java - Done
2018-12-11 11:04:54.508 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='4eac7884-3374-494a-a549-fcd7505fc5b4', mState=ENQUEUED, mOutputData=androidx.work.Data@0, mTags=[finally, com.plangrid.android.workmanager.FinalWorker]}
2018-12-11 11:04:54.509 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='c8e75590-8f60-40b7-a2e6-4e7aa6e7830d', mState=SUCCEEDED, mOutputData=androidx.work.Data@0, mTags=[com.plangrid.android.workmanager.DownloadCommentsWorker]}
2018-12-11 11:04:54.518 6991-7057/com.plangrid.android.devgrid I/System.out: ALL WORK COMPLETE
2018-12-11 11:04:54.528 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='4eac7884-3374-494a-a549-fcd7505fc5b4', mState=SUCCEEDED, mOutputData=androidx.work.Data@0, mTags=[finally, com.plangrid.android.workmanager.FinalWorker]}
2018-12-11 11:04:54.528 6991-6991/com.plangrid.android.devgrid I/System.out: WorkInfo{mId='c8e75590-8f60-40b7-a2e6-4e7aa6e7830d', mState=SUCCEEDED, mOutputData=androidx.work.Data@0, mTags=[com.plangrid.android.workmanager.DownloadCommentsWorker]}
```