A fake AP should be the current access point. The code in act_stage1_prepare
violated this invariant for a short time by emitting signals before
setting current_ap. Reorder statements, so that
  - fake AP gets created and added to ap_list
  - fake AP gets set as current_ap (suppressing notify signals)
  - emit ACCESS_POINT_ADDED signal
  - thaw notify::NM_DEVICE_WIFI_ACTIVE_ACCESS_POINT signal

When performing a series of actions that emit several signals, it is
often difficult to emit them in an order, so that listeners get a
consistent view. With this change, listeners will get ACCESS_POINT_ADDED
signal, and the current ap already being set to the fake_ap. Next they
get notify::NM_DEVICE_WIFI_ACTIVE_ACCESS_POINT. There is no perfect
solution, but this way it makes slightly more sense.

Signed-off-by: Thomas Haller <thaller@redhat.com>