It is bound to autoconnect_inhibit private variable (has opposite meaning).
While 'Autoconnect' is TRUE (default value) the device can automatically
activate a connection. If it is changed to FALSE, the device will not
auto-activate until 'Autoconnect' is TRUE again.
Disconnect() method sets 'Autoconnect' to FALSE. NMPolicy monitors the property
and schedules auto activation when FALSE->TRUE transition is made.