When iwd restarts it recreates wlan0 under a new D-Bus path. Only the
Station interface was tracked on InterfacesAdded, so devicePath kept
pointing at the dead object: the PropertiesChanged match for the new
device was never registered, updateState() read Powered from the old
path, and SetWiFiEnabled() failed with "No matching method found".
WiFiEnabled stayed false after handleStationRemoved() until DMS was
restarted.
Handle the Device interface on InterfacesAdded/InterfacesRemoved: move
devicePath and its signal match to the new object and take Name and
Powered from the signal. Process every interface in an
InterfacesRemoved signal instead of stopping at the first match.
Refs #3495
Pedro Jose Soto Rivera
ff50b492b1