Task #9127: ObservationStartListener: improve fmt of lofarlogger for shell scripts

LCS/MessageDaemons/ObservationStartListener/src/lofarlogger.sh

 # lofarlogger.sh
 #
-# Copyright (C) 2015
+# Copyright (C) 2015-2016
 # ASTRON (Netherlands Institute for Radio Astronomy)
 # P.O.Box 2, 7990 AA Dwingeloo, The Netherlands
 #
@@ -22,12 +22,17 @@
 
 # Usage: source lofarlogger.sh
 # then e.g.: log INFO "foo bar"
-# logs e.g.: 2015-10-16 16:00:46,186 INFO foo bar
+# logs e.g.: 2015-10-16 16:00:46,186 INFO - foo bar
 
 log() {
-  loglevel=$1  # one of: DEBUG INFO WARNING ERROR CRITICAL
+  loglevel=$1  # one of: DEBUG INFO WARN ERROR FATAL
   message=$2
   ts=`date --utc '+%F %T,%3N'`  # e.g. 2015-10-16 16:00:46,186
-  echo "$ts $loglevel $message" >&2
+  echo "$ts $loglevel - $message" >&2
+}
+
+fatal() {
+  log $1
+  exit 1
 }