Removed unneeded usings.

Author: grokys

src/GitHub.App/Factories/RepositoryHostFactory.cs

@@ -1,14 +1,12 @@
 using System;
 using System.ComponentModel.Composition;
-using GitHub.Authentication;
 using GitHub.Caches;
 using GitHub.Models;
 using GitHub.Primitives;
 using GitHub.Services;
 using System.Reactive.Disposables;
 using System.Threading.Tasks;
 using GitHub.Api;
-using IObservableKeychainAdapter = GitHub.Caches.IObservableKeychainAdapter;
 
 namespace GitHub.Factories
 {

src/GitHub.App/Models/RepositoryHost.cs

@@ -16,7 +16,6 @@
 using NLog;
 using Octokit;
 using ReactiveUI;
-using IObservableKeychainAdapter = GitHub.Caches.IObservableKeychainAdapter;
 
 namespace GitHub.Models
 {