networkmanager priority changes on dist upgrade to 16.04

[dronus]

After upgrading from Ubuntu 14.04 to Ubuntu 16.04, the Network manager behaviour changed regarding to the priorities of networks.

I have several AdHoc-network definitions, that are now activated in favor of my home WiFi connection. I had to remove the autoconnect option on all of them, as even after using Ubuntu 16.04 some time, NetworkManager still sometimes decided to pick one of the AdHoc connections in favor of the home WiFi (the AdHoc networks are established anew, there is no such network available for scanning).

Maybe if NetworkManager now uses a new system, the update process should change the settings of each connection accordingly.

I however wonder if this is a deeper bug, making the old behaviour impossible (to autoconnect to an existing AdHoc network if available, but connect to the default AP if not).