IPS: Do not try to show rules when stat on rules tarball fails

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

html/cgi-bin/ids.cgi

@@ -1091,6 +1091,7 @@ if (%idsrules) {
 	# Call stat on the rulestarball.
 	my $stat = stat("$IDS::rulestarball");
 
+	if (defined $stat) {
 		# Get timestamp the file creation.
 		my $mtime = $stat->mtime;
 
@@ -1200,6 +1201,7 @@ END
 ;
 		&Header::closebox();
 	}
+}
 
 &Header::closebigbox();
 &Header::closepage();