Fix to prefer /var/cache or /var/tmp over /tmp for default temp directory

web-lib-funcs.pl

@@ -448,7 +448,13 @@ configuration or environment override is set.
 =cut
 sub default_webmin_temp_dir
 {
-return -d "c:/temp" ? "c:/temp" : "/tmp/.webmin";
+return -d "c:/temp"
+	? "c:/temp"
+	: -d "/var/cache"
+		? "/var/cache/webmin"
+		: -d "/var/tmp"
+			? "/var/tmp/webmin"
+			: "/tmp/.webmin";
 }
 
 =head2 tempname_dir()