Revert "install-chef-suse.sh: Add xinetd, otherwise setup script fails"

This reverts commit 17e5455fedb6a876ccc5c22666262e6cfada8490.

We'll fix the root cause in the provisioner barclamp cookbook, instead
of working around it here. See the pull review discussion for details:

https://github.com/crowbar/crowbar/pull/1816#discussion_r4397270
install-chef-suse.sh: Use --force only when from Git

As suggested by Ralf during patch review.