- added check if host is defined

lib/SLUB/LZA/TA/Archivematica/Elasticsearch.pm

@@ -19,6 +19,7 @@ our @EXPORT_OK = qw();
 #$Search::Elasticsearch::Error::DEBUG=2;
 
 sub _instantiate($protocol, $host, $port) {
+    die "No host configuration found, missed config-file or command line parameter?\nHint: check '$0' help init'\n" unless defined $host;
     return Search::Elasticsearch->new(
         nodes    => "$protocol://$host:$port",
         #trace_to => 'Stderr',