Services.AddOptions() ambiguous
<p>I am busy migrating our ASP.NET Core API from RC1 to RC2.</p>

<p>RC2 requires that <a href="https://docs.asp.net/en/latest/fundamentals/configuration.html">we configure the following</a> when using <code>IOptions&lt;T&gt;</code>:</p>

<pre><code>services.AddOptions();
</code></pre>

<p>But I get the following compilation error:</p>

<blockquote>
  <p>Error CS0121  The call is ambiguous between the following methods or
  properties:
  'Microsoft.Extensions.DependencyInjection.OptionsServiceCollectionExtensions.AddOptions(Microsoft.Extensions.DependencyInjection.IServiceCollection)'
  and
  'Microsoft.Extensions.DependencyInjection.OptionsServiceCollectionExtensions.AddOptions(Microsoft.Extensions.DependencyInjection.IServiceCollection)' TransitApi.Api..NET
  Framework 4.5.2</p>
</blockquote>

<p>These are the exact same extension methods! I have tried deleting all packages and deleting the lock files, but to no avail.</p>

<p>The project.json:</p>

<pre><code>{
  "title": "MyProject.Api",
  "webroot": "wwwroot",
  "version": "1.0.0-*",
  "dependencies": {

    "Microsoft.ApplicationInsights.AspNetCore": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Mvc": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Diagnostics": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Authorization": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Mvc.Core": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Mvc.Abstractions": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Authentication.JwtBearer": "1.0.0-rc2-final",
    "Microsoft.Extensions.PlatformAbstractions": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.StaticFiles": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging.Abstractions": "1.0.0-rc2-final",
    "Microsoft.Extensions.Logging.Console": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Http": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Http.Abstractions": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.Json": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0-rc2-final",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0-rc2-final",
    "Newtonsoft.Json": "8.0.3",
    "WindowsAzure.Storage": "7.0.0",
    "Microsoft.AspNetCore.Mvc.Formatters.Json": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0-rc2-final",
    "Microsoft.AspNetCore.Cors": "1.0.0-rc2-final"
  },
  "frameworks": {
    "net452": { }
  },
  "tools": {
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": {
      "version": "1.0.0-preview1-final",
      "imports": "portable-net45+win8+dnxcore50"
    }
  },
  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },
  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },
  "publishOptions": {
    "include": [
      "wwwroot",
      "appsettings.json",
      "web.config"
    ]
  }
}
</code></pre>