LTI - external tool - "Force SSL" setting will not save as unchecked once it is saved checked in a tool configuration

If an LTI tool configuration has the forcessl setting checked and is saved, then if a user tries to edit the configuration and unset it when it is saved it does not stick.

Steps to replicate:

1. As an admin navigate to Site administration -> Plugins -> Activity modules -> LTI -> Manage external tool types
2. Click "Add external tool configuration"
   1. Add any name, tool url (not relevant to this issue)
3. Under the "Privacy" section check the "Force SSL" checkbox
4. Click "Save changes"
5. Edit the tool configuration you just created by clicking the settings icon
6. Under the "Privacy" section uncheck the "Force SSL" checkbox
7. Click "Save changes"
8. Edit the tool configuration you just created by clicking the settings icon

Result: The "Force SSL" setting will still be checked