"Analytics requires Google App ID from GoogleService-Info.plist. Your data may be lost. Google App ID has been changed. Original, new ID: (nil), XXXXXXXXXXXXXXXX"について

# 現象

iOSにてFirebaseを組み込んで起動した際に以下のログが出ていた。

- Firebase4.0.0
- Xcode8.3.2
- Swift3.1

```
<Error> [Firebase/Core][I-COR000012] Could not locate configuration file: 'GoogleService-Info.plist'.
<Error> [Firebase/Analytics][I-ACS020006] Google App ID from GoogleService-Info.plist is empty. Please, define GOOGLE_APP_ID in GoogleService-Info.plist for Analytics to work reliably.
<Error> [Firebase/Analytics][I-ACS025020] Analytics requires Google App ID from GoogleService-Info.plist. Your data may be lost. Google App ID has been changed. Original, new ID: (nil), X:XXXXXXXXXXXXXXXXX
```

# 理由

`GoogleService-Info.plist`を**GoogleService-Info-XXX.plist**のようにリネームして読み込んでいると上記のエラーログが出力される。

ただ動作としては問題なく動く。

# 補足

[scheme毎にGoogleService-Info.plistを切り替える](http://qiita.com/noboru_i/items/5d23daae651e48fb3feb)と同じように複数のGoogleService-Info.plistをscheme毎に切り替えて開発をしていた。

GoogleService-Info-XXX.plistをGoogleService-Info.plistにリネームしたらエラーは出なくなった。

リネーム前とリネーム後のログのdiff

```diff
--- a/log   2017-05-26 17:54:58.000000000 +0900
+++ b/log    2017-05-26 17:55:08.000000000 +0900
@@ -1,15 +1,9 @@
  [Crashlytics] Version 3.8.4 (121)
  [MC] System group container for systemgroup.com.apple.configurationprofiles path is /private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles
  [MC] Reading from public effective user settings.
- [Firebase/Core][I-COR000012] Could not locate configuration file: 'GoogleService-Info.plist'.
- <Error> [Firebase/Core][I-COR000012] Could not locate configuration file: 'GoogleService-Info.plist'.
- [Firebase/Analytics][I-ACS020006] Google App ID from GoogleService-Info.plist is empty. Please, define GOOGLE_APP_ID in GoogleService-Info.plist for Analytics to work reliably.
- <Error> [Firebase/Analytics][I-ACS020006] Google App ID from GoogleService-Info.plist is empty. Please, define GOOGLE_APP_ID in GoogleService-Info.plist for Analytics to work reliably.
  [Firebase/Messaging][I-FCM001000] FIRMessaging Remote Notifications proxy enabled, will swizzle remote notification receiver handlers. Add "FirebaseAppDelegateProxyEnabled" to your Info.plist and set it to NO
  <Notice> [Firebase/Messaging][I-FCM001000] FIRMessaging Remote Notifications proxy enabled, will swizzle remote notification receiver handlers. Add "FirebaseAppDelegateProxyEnabled" to your Info.plist and set it to NO
- [Firebase/Analytics][I-ACS025020] Analytics requires Google App ID from GoogleService-Info.plist. Your data may be lost. Google App ID has been changed. Original, new ID: (nil), X:XXXXXXXXXXXXXX
- <Error> [Firebase/Analytics][I-ACS025020] Analytics requires Google App ID from GoogleService-Info.plist. Your data may be lost. Google App ID has been changed. Original, new ID: (nil), X:XXXXXXXXXXXXXX
  [Firebase/Analytics][I-ACS023007] Firebase Analytics v.4000000 started
  <Notice> [Firebase/Analytics][I-ACS023007] Firebase Analytics v.4000000 started
  [Firebase/Analytics][I-ACS023008] To enable debug logging set the following application argument: -FIRAnalyticsDebugEnabled (see http://goo.gl/RfcP7r)
```

エラーが消えていることがわかる。
ただ運用上複数使いたいのでこのエラーは無視している。