Handle Http.Core rename.

Author: Tratcher

test/Microsoft.AspNet.StaticFiles.Tests/DefaultFilesMiddlewareTests.cs

@@ -9,7 +9,6 @@
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.FileProviders;
 using Microsoft.AspNet.Http;
-using Microsoft.AspNet.Http.Core;
 using Microsoft.AspNet.TestHost;
 using Xunit;
 

test/Microsoft.AspNet.StaticFiles.Tests/StaticFileContextTest.cs

@@ -6,7 +6,6 @@
 using System.IO;
 using Microsoft.AspNet.FileProviders;
 using Microsoft.AspNet.Http;
-using Microsoft.AspNet.Http.Core;
 using Microsoft.Framework.Expiration.Interfaces;
 using Microsoft.Framework.Logging.Testing;
 using Xunit;

test/Microsoft.AspNet.StaticFiles.Tests/project.json

@@ -1,6 +1,5 @@
 {
     "dependencies": {
-        "Microsoft.AspNet.Http.Core": "1.0.0-*",
         "Microsoft.AspNet.StaticFiles": "1.0.0-*",
         "Microsoft.AspNet.TestHost": "1.0.0-*",
         "Microsoft.Framework.Logging.Testing": "1.0.0-*",