Forces amount_extra to 0 if it's too high
Forces amount_extra to 0 if it's too high

Changes the amount_extra to 0 if it goes over the Super Sponsor price.
We should fix the core problem of the session going off kilter, but this
is a stopgap until then.

migetman9/ubersystem,magfest/ubersystem,migetman9/ubersystem,migetman9/ubersystem,magfest/ubersystem,RAMSProject/rams,RAMSProject/rams,md1024/rams,magfest/ubersystem,RAMSProject/rams,magfest/ubersystem,md1024/rams,md1024/rams