Make firefox stop trying to force https for a site

Recent builds of firefox, if they have ever seen https on a particular hostname, will refuse to ever again load http from that hostname, even if the name moves to a different server or owner or whatever. If it does this, the only way to fix it is to manually remove entries for that host from a private sqlite db it keeps.

$ sqlite3 /home/.mozilla/forefox/BLABLABLA.default/permissions.sqlite
sqlite> delete from moz_hosts where host = "hostname.com";
sqlite3> quit
$