This reverts commit cc1920d7, reversing
changes made to eb8257de.

This breaks restart, at least for Wi-Fi devices:

    #0  0x00007ffff5ee8771 in _g_log_abort (breakpoint=breakpoint@entry=1) at gmessages.c:554
    #1  0x00007ffff5ee9a5b in g_logv (log_domain=0x7ffff671a738 "GLib-GIO", log_level=G_LOG_LEVEL_CRITICAL, format=<optimized out>, args=args@entry=0x7fffffffd720) at gmessages.c:1362
    #2  0x00007ffff5ee9baf in g_log (log_domain=log_domain@entry=0x7ffff671a738 "GLib-GIO", log_level=log_level@entry=G_LOG_LEVEL_CRITICAL, format=format@entry=0x7ffff5f347ea "%s: assertion '%s' failed") at gmessages.c:1403
    #3  0x00007ffff5eea0f9 in g_return_if_fail_warning (log_domain=log_domain@entry=0x7ffff671a738 "GLib-GIO", pretty_function=pretty_function@entry=0x7ffff673fc10 <__func__.25628> "g_dbus_proxy_call_internal", expression=expression@entry=0x7ffff673fb1c "G_IS_DBUS_PROXY (proxy)") at gmessages.c:2702
    #4  0x00007ffff66cdc5f in g_dbus_proxy_call_internal (proxy=0x0, method_name=method_name@entry=0x555555810510 "Scan", parameters=0x555555c7a530, flags=flags@entry=G_DBUS_CALL_FLAGS_NONE, timeout_msec=timeout_msec@entry=-1, fd_list=fd_list@entry=0x0, cancellable=0x0, callback=0x55555574cb96 <scan_request_cb>, user_data=0x555555ac2220) at gdbusproxy.c:2664
    #5  0x00007ffff66cf686 in g_dbus_proxy_call (proxy=<optimized out>, method_name=method_name@entry=0x555555810510 "Scan", parameters=<optimized out>, flags=flags@entry=G_DBUS_CALL_FLAGS_NONE, timeout_msec=timeout_msec@entry=-1, cancellable=cancellable@entry=0x0, callback=0x55555574cb96 <scan_request_cb>, user_data=0x555555ac2220) at gdbusproxy.c:2970
    #6  0x000055555574e026 in nm_supplicant_interface_request_scan (self=0x555555ac2220 [NMSupplicantInterface], ssids=ssids@entry=0x0) at src/supplicant/nm-supplicant-interface.c:1821
    #7  0x00007fffe1038276 in request_wireless_scan (self=self@entry=0x555555c6ee60 [NMDeviceWifi], periodic=periodic@entry=0, force_if_scanning=force_if_scanning@entry=0, ssids=<optimized out>, ssids@entry=0x0) at src/devices/wifi/nm-device-wifi.c:1347
    #8  0x00007fffe1039011 in device_state_changed (device=0x555555c6ee60 [NMDeviceWifi], new_state=NM_DEVICE_STATE_DISCONNECTED, old_state=<optimized out>, reason=<optimized out>)
        at src/devices/wifi/nm-device-wifi.c:2998
    #9  0x00007ffff432ed1e in ffi_call_unix64 () at ../src/x86/unix64.S:76
    #10 0x00007ffff432e68f in ffi_call (cif=cif@entry=0x7fffffffdc70, fn=fn@entry=0x7fffe1038e1e <device_state_changed>, rvalue=<optimized out>, avalue=avalue@entry=0x7fffffffdb60)
        at ../src/x86/ffi64.c:525
    #15 0x00007ffff63db66f in <emit signal ??? on instance 0x555555c6ee60 [NMDeviceWifi]> (instance=instance@entry=0x555555c6ee60, signal_id=<optimized out>, detail=detail@entry=0)
        at gsignal.c:3447
        #11 0x00007ffff63bff39 in g_cclosure_marshal_generic (closure=0x555555c22ea0, return_gvalue=0x0, n_param_values=<optimized out>, param_values=<optimized out>, invocation_hint=<optimized out>, marshal_data=<optimized out>) at gclosure.c:1490
        #12 0x00007ffff63bf73d in g_closure_invoke (closure=0x555555c22ea0, return_value=0x0, n_param_values=4, param_values=0x7fffffffdea0, invocation_hint=0x7fffffffde20) at gclosure.c:804
        #13 0x00007ffff63d1f30 in signal_emit_unlocked_R (node=node@entry=0x555555c22750, detail=detail@entry=0, instance=instance@entry=0x555555c6ee60, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffffffdea0) at gsignal.c:3673
        #14 0x00007ffff63dad05 in g_signal_emit_valist (instance=0x555555c6ee60, signal_id=<optimized out>, detail=0, var_args=var_args@entry=0x7fffffffe0b0) at gsignal.c:3391
    #16 0x00005555556f0f18 in _set_state_full (self=self@entry=0x555555c6ee60 [NMDeviceWifi], state=state@entry=NM_DEVICE_STATE_DISCONNECTED, reason=reason@entry=NM_DEVICE_STATE_REASON_CONNECTION_ASSUMED, quitting=quitting@entry=0) at src/devices/nm-device.c:13268
    #17 0x00005555556f1774 in nm_device_state_changed (self=self@entry=0x555555c6ee60 [NMDeviceWifi], state=state@entry=NM_DEVICE_STATE_DISCONNECTED, reason=reason@entry=NM_DEVICE_STATE_REASON_CONNECTION_ASSUMED) at src/devices/nm-device.c:13435
    #18 0x00005555555bcf95 in recheck_assume_connection (self=self@entry=0x555555b09140 [NMManager], device=device@entry=0x555555c6ee60 [NMDeviceWifi]) at src/nm-manager.c:2297
    #19 0x00005555555bd53e in _device_realize_finish (self=self@entry=0x555555b09140 [NMManager], device=device@entry=0x555555c6ee60 [NMDeviceWifi], plink=plink@entry=0x555555ae43d8)
        at src/nm-manager.c:2473
    #20 0x00005555555c01d0 in platform_link_added (self=self@entry=0x555555b09140 [NMManager], ifindex=<optimized out>, plink=plink@entry=0x555555ae43d8, guess_assume=<optimized out>, dev_state=<optimized out>) at src/nm-manager.c:2789
    #21 0x00005555555c0cec in platform_query_devices (self=self@entry=0x555555b09140 [NMManager]) at src/nm-manager.c:2901
    #22 0x00005555555c439e in nm_manager_start (self=0x555555b09140 [NMManager], error=<optimized out>) at src/nm-manager.c:5632
    #23 0x000055555558498e in main (argc=<optimized out>, argv=<optimized out>) at src/main.c:413