Makefile paths for install and uninstall are different

[heurekus]

In the current makefile, the paths for adding and removing wondershaper as a service are different. Thus, I had to remove the files manually when uninstalling wondershaper. Looks like a bug to me.

Note: I uninstalled wondershaper as a service (for now) as after a reboot, the service is started on Ubuntu 20.04 desktop, but it seems it's too early and the settings aren't applied to my Wifi interface. Works fine if started manually after the Wifi interface is up though, so thank you!

[heurekus]

Ah, looks like pull request #62 addresses the same topic :)