Have no notice when state changed after a task is disabled and re-enabled.

Hi,

Kapacitor version: 0.13

My scenario is:
1. create a task A
2. change the value of metric greater than threshold to trigger an alert (I can receive a notice that an alert is triiggerd)
3. disable the task A
4. change the value of metric lower than threshold
5. enable the task A

I want to receive a notice of OK when the task is re-enabled.

But, there is no either notice.

I find the DOT is clean when disable and re-enable a task.

I think this is a useful feature.

How about you?

Thanks

No file, test, or entry point is named. Start by reproducing the disable/re-enable scenario on Kapacitor 0.13 and inspect the task's state and DOT output around re-enabling. Done means the task emits an OK notice after the metric falls below the threshold while the task was disabled.

Written by the indexing model from the issue text.