Possible race between config checker on app start and applying a config at runtime

[jjcarstens]

Describe the bug
I'm noticing this within the nerves_examples/hello_wifi repo. After burning a new image, the first run attempts to start the wifi wizard but it fails silently to put the device in AP mode (the other wizard processes are started)

00:10:40.765 [warn]  STARTING WIFI WIZARD

00:10:40.772 [info]  VintageNet(wlan0): loading config failed: :enoent

00:10:40.773 [info]  VintageNet(wlan0): starting with default config (:no_config)

To Reproduce
Steps to reproduce the behavior:

1. burn a new image of nerves_examples/hello_wifi
2. run on a device
3. See if device successfully started the AP

VintageNet Info

iex(2)> VintageNet.info
VintageNet 0.7.6

All interfaces:       ["lo", "usb0", "wlan0"]
Available interfaces: []

Interface usb0
  Type: VintageNetDirect
  Present: true
  State: :configured
  Connection: :lan
  Configuration:
    %{type: VintageNetDirect, vintage_net_direct: %{}}

Environment

jonjon@ 📂 {hello_wifi} $ mix nerves.env --info
|nerves_bootstrap| Environment Package List

  Pkg:         nerves_system_rpi0
  Vsn:         1.11.0
  Type:        system
  BuildRunner: {Nerves.Artifact.BuildRunners.Docker, []}

  Pkg:         nerves_toolchain_armv6_rpi_linux_gnueabi
  Vsn:         1.3.1
  Type:        toolchain
  BuildRunner: {Nerves.Artifact.BuildRunners.Local, []}

  Pkg:         nerves_system_br
  Vsn:         1.11.0
  Type:        system_platform
  BuildRunner: {nil, []}

  Pkg:         nerves_toolchain_ctng
  Vsn:         1.7.1
  Type:        toolchain_platform
  BuildRunner: {nil, []}

|nerves_bootstrap| Loadpaths Start


Nerves environment
  MIX_TARGET:   rpi0
  MIX_ENV:      dev

|nerves_bootstrap| Environment Variable List
  target:     rpi0
  toolchain:  /Users/jonjon/.nerves/artifacts/nerves_toolchain_armv6_rpi_linux_gnueabi-darwin_x86_64-1.3.1
  system:     /Users/jonjon/.nerves/artifacts/nerves_system_rpi0-portable-1.11.0
  app:        /Users/jonjon/repos/nerves_examples/hello_wifi

|nerves_bootstrap| Loadpaths End

Additional context
I haven't tested with anything besides rpi0 which also attempts to add usb0 interface. I'm not sure if that is potentially interfering