I had this problem only I forgot my gmail password cuz I never use it. I fixed it. This only works if you have a shortcut to your settings on your home screen.
When on the screen with gmail and password theres a emergency call option, select it.
on the call screen press back, you have a split second to select settings.
do it again when you press back it should show your settings menu
you have to be quick and press security
do it again and you should see the require pattern option at the very top.
the next time your on that screen you have enter your pattern as quick as possible, and that should solve the problem.
this will take a few attempts and be very frustrating, but be patient and you wont have to wipe your phone