exp:channel:form throws session overload when logged out and logged_out_member_id param used

This bug relates to one filed by Greg Ferrell here: https://ellislab.com/forums/viewthread/248348/

This happens native to EE 3 though. The channel entries add-on also tries to manipulate the ee()->session object just as a number of 3rd party add-ons do. Perhaps the fix for this will also help us out.

Exception Caught Cannot overwrite session on the loader.

/Users/mk/Sites/ee300/system/ee/EllisLab/ExpressionEngine/Legacy/Facade.php:83 Stack Trace: show

Steps to reproduce:

1. Add this in a template {exp:channel:form channel="some_channel" logged_out_member_id="1"} hiya {/exp:channel:form}

2. Be logged out.

3. Go to that page.