Allow key file reference to not exist

[J D]

Whenever you save a configuration in the site manager, it is possible to select the key file for the logon type.

Unfortunately, the key file always has to exist in order to be able to leave the configuration. I have some key files on external devices and therefore the path is not always available. When I want to connect to another configuration, I can not click on this configuration since the still open configuration gives me an error the key file can not be found.

Steps to reproduce

1. Create site A, choose for logon type 'key file'
2. Add a key file from an existing location
3. Create site B, it does not matter what you configure here
4. Connect to site A
5. Close filezilla
6. The last item you connected to was Site A, so this is still selected in the Site manager. Now delete the key file (or move it) like you are disconnecting the storage volume the key file is stored on.
7. Try connecting to site B. This is not possible due to the key file not existing.

Since it does not matter our key file is not available at this moment, since we are trying to connect to Site B (not A), this error should not be in the way of selecting another configuration.