bug 1291892 - Cleanup session on account creation
bug 1291892 - Cleanup session on account creation

After a user account is successfully created from a social login, clear
the initial signin data from the session, so that the user can connect
a second account immediately without triggering the 'invalid account
connection' logic in pre_social_login.

mozilla/kuma,yfdyh000/kuma,safwanrahman/kuma,yfdyh000/kuma,jwhitlock/kuma,Elchi3/kuma,jwhitlock/kuma,mozilla/kuma,safwanrahman/kuma,safwanrahman/kuma,Elchi3/kuma,Elchi3/kuma,mozilla/kuma,ollie314/kuma,safwanrahman/kuma,safwanrahman/kuma,Elchi3/kuma,a2sheppy/kuma,escattone/kuma,Elchi3/kuma,escattone/kuma,SphinxKnight/kuma,escattone/kuma,yfdyh000/kuma,SphinxKnight/kuma,safwanrahman/kuma,yfdyh000/kuma,ollie314/kuma,mozilla/kuma,a2sheppy/kuma,mozilla/kuma,ollie314/kuma,jwhitlock/kuma,SphinxKnight/kuma,yfdyh000/kuma,ollie314/kuma,SphinxKnight/kuma,jwhitlock/kuma,a2sheppy/kuma,SphinxKnight/kuma,ollie314/kuma,a2sheppy/kuma,yfdyh000/kuma,jwhitlock/kuma,SphinxKnight/kuma,ollie314/kuma,a2sheppy/kuma