Remove config_backend from examples

[deric]

Parameter config_backend has been removed in #373.

[cla-bot]

Thank you for your pull request. Before we can look at it, you'll need to sign a Contributor License Agreement (CLA).

Please follow instructions at https://icinga.com/company/contributor-agreement to sign the CLA.

After that, please reply here with a comment and we'll verify.

Contributors that have not signed yet: @deric

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Please contact us if you think this is the case.

• If you signed the CLA as a corporation, your GitHub username may not have been submitted to us. Please reach out to the responsible person in your organization.

[deric]

@cla-bot signed

[lbetz]

Ups, the examples. Thx so much.

[bobapple]

@cla-bot check