Default service names in examples, druid-code and tranquility should match

[nishantmonu51]

Follow up on comment https://github.com/druid-io/druid/pull/2015/files#r46606495

We need to modify the default serviceName in druid-examples and tranquility to match defaults in druid code.

[stale]

This issue has been marked as stale due to 280 days of inactivity. It will be closed in 2 weeks if no further activity occurs. If this issue is still relevant, please simply write any comment. Even if closed, you can still revive the issue at any time or discuss it on the dev@druid.apache.org list. Thank you for your contributions.

[stale]

This issue has been closed due to lack of activity. If you think that is incorrect, or the issue requires additional review, you can revive the issue at any time.