Setting the WiFi network interface up or down is racy because it
is not synchronized with the WiFi components managing the interface.
This causes a problem for hostapd when the interface is marked down
before hostapd starts because it causes the driver to enter the
de-initialization process. hostapd does not know how to react to this
change of events.
Bug: 31205821
Test: bug no longer reproduces on upcoming devices, unit tests pass
Change-Id: I96938e2aef89b400593d42ce1b0a6ccc2d2e5754
ce5d913387