Erase Foxfi lock screen for android re-enable pattern lock

Android system enforces the screen lock when you
install the FoxFi certificate (which is needed to bypass a tether plan
with the latest carrier/firmware blockage). When you are done using
FoxFi,
simply select Settings->Security&Screen Lock->Clear Credentials
(Motorola Phones) or Settings->More->Security->Clear Credentials
(Samsung phones). This will remove the FoxFi certificate and after that
you will be able to set Screen Lock to "None".