Don't fail if not domain is defined in zmldapsync conf

zmldapsync/zmldapsync.pl

@@ -72,6 +72,11 @@ my $uuid     = Data::UUID->new();
 my $exit     = 0;
 my $err      = '';
 
+if (not defined $conf->{domains} or ref $conf->{domains} ne 'HASH'){
+  print "No domain configured for LDAP sync, nothing to do\n";
+  exit (0);
+}
+
 DOMAIN: foreach my $domain ( keys $conf->{domains} ) {
   log_verbose( "Start to process domain $domain" );