simplify syntax when setting a non-nil value
remove node_modified as it's always true

(it was being set to true on line 61)
On SLES12 use a systemd unit file to manage crowbar_join

This helps us blocking the chef-client daemon from starting before crowbar_join
is finished.
Bugfix: hostname: Host name lookup failure

Bug: https://bugzilla.novell.com/show_bug.cgi?id=886238

Fixed the bug: If the /etc/resolv.conf is broken, "hostname -f" could not say
the hostname of the current host.

Resolution: Added a new entry in the /etc/hosts file. (IP, FQDN & Hostname)
Merge pull request #340 from mapleoin/cleanup

Cleanup some useless code
Cleanup some unneeded only_if/nof_if guards

The chef resources already to the right thing without them
Use the service resource for handing the crowbar_join service

It's a lot cleaner the calling chkconfig directly and we can move it outside
the if clause to share the code with SLE12.
Merge pull request #344 from mschnitzer/master

Bugfix: hostname: Host name lookup failure
Merge pull request #342 from rhafer/crowbar_join-systemd

On SLES12 use a systemd unit file to manage crowbar_join
handle multiple NTP servers (bnc#895824)

sntp seems to use only the first NTP server and ignore others,
so we iterate over the list and stop waiting when we find a working one
https://bugzilla.novell.com/show_bug.cgi?id=895824