As far as I know it is only listed in the addons.cfg file if you add it there.
Stuff that is installed via the UI is normally listed in the jsondb directory.
You did not add it to the addons folder ( which depends on the OS/environment ) /usr/share/openhab/addons ?
I would try if steps that are listed in this thread HowTo correctly remove a Smarthome/J binding? also help in your case.