examples: get bluez-session working again

I'm getting this error when trying to run the bluez-session example:

[E][02799.665601] spa.bluez5   | [   bluez5-dbus.c: 5941 impl_init()] failed to parse quirk table

This turns out to be caused by this line. This is because we parsed NULL for info when initializing the bluez5 dbus plugin. So, add an empty dict here, to prevent this error.

Also, there's an invalid free to be corrected.