.htaccess: Options not allowed here

cf: https://serverfault.com/questions/680563/apache-2-4-9-on-debian-7-8-htaccess-options-not-allowed

Edit /etc/apache2/mods-enabled/userdir.conf, change the line

AllowOverride FileInfo AuthConfig Limit Indexes

to

AllowOverride FileInfo AuthConfig Limit Indexes Options