reference: shorten logchange log message

Remove the "adjustment started" part from the "System clock wrong by *
seconds, adjustment started" log message as it might be confusing in
some cases. There may be a step instead of a slow adjustment, or there
may be no adjustment at all when running with the -x option.

reference.c

@@ -489,8 +489,7 @@ maybe_log_offset(double offset, time_t now)
   abs_offset = fabs(offset);
 
   if (abs_offset > log_change_threshold) {
-    LOG(LOGS_WARN, "System clock wrong by %.6f seconds, adjustment started",
-        -offset);
+    LOG(LOGS_WARN, "System clock wrong by %.6f seconds", -offset);
   }
 
   if (do_mail_change &&