After updating to Tumbleweed 20190805, the wireless interface is not started
during boot anymore and the following errors show up in the log:

wickedd[766]: ni_wpa_interface_bind(wlan0): Operation not permitted
wickedd[766]: wpa_supplicant doesn't know interface wlan0
wickedd-nanny[768]: device wlan0: call to
org.opensuse.Network.Wireless.changeDevice() failed: General failure
wickedd-nanny[768]: wlan0: failed to bring up device, still continuing
wicked[769]: lo              setup-in-progress
wicked[769]: wlan0           device-not-running


Since I noticed that the latest update changed the starting order of
wpa_supplicant.service, I tried to revert it.
By simply adding back

Before=network.target

in /usr/lib/systemd/system/wpa_supplicant.service
the booting process is back to normal with a working wifi.