fix ntp.conf config merging: do reread the config from disk (bnc#773201)

Peter's original fix from
https://bugzilla.novell.com/show_bug.cgi?id=773201#c3
https://build.suse.de/request/show/21223
clarified a debug message, not repeating a failed call.
reverted some useless debugging

param is unused
and the caller already logs whether func is Info or Write.
changelog, version
Merge pull request #2 from mvidner/Code-11-SP3

fix ntp.conf config merging: do reread the config from disk (bnc#773201)