prevent adhoc_kill_splunkd.yml from running by default when upgrading

[jewnix]

This stops the adhoc_kill_splunkd.yml task from running during upgrade by default.

A few reasons for this change.

1. In some cases killing it forcefully is not a safe way to go, especially if the instance is busy.
2. There are also cases when there are multiple instances running on the same host with a different $SPLUNK_HOME, and this will kill all splunk processes
3. If there are docker containers running the splunk process in them, this can cause some serious issues.