Support systemd natively

[mfortin]

https://docs.splunk.com/Documentation/Splunk/8.0.4/Admin/RunSplunkassystemdservice

Description

Make the service systemd native when supported.

Issues Resolved

#156

Check List

• All tests pass. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
• New functionality includes testing.
• New functionality has been documented in the README if applicable
• All commits have been signed for the Developer Certificate of Origin. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[haidangwa]

@mfortin A DCO sign-off is needed. You can do this by modifying your commit message and add Signed-off-by: your name <your email> to the message. git log will show you plenty of examples.

Also, ensure that tests are passing. The report shows that one step is failing.

[mfortin]

@haidangwa done, added the DCO.

[haidangwa]

@mfortin Thanks! I'll accept the merge, since the chefspec failure we're seeing is an existing failure from the master branch that needs to be fixed elsewhere.