Fixed remaining namespace changes

Author: davidfowl

samples/SampleApp/Startup.cs

@@ -6,7 +6,7 @@
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Features;
 using Microsoft.AspNet.Server.Kestrel;
-using Microsoft.Dnx.Runtime;
+using Microsoft.Extensions.PlatformAbstractions;
 using Microsoft.Extensions.Logging;
 
 #if DNX451

test/Microsoft.AspNet.Server.Kestrel.FunctionalTests/AddressRegistrationTests.cs

@@ -8,7 +8,6 @@
 using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Extensions;
-using Microsoft.Dnx.Runtime.Infrastructure;
 using Microsoft.Extensions.Configuration;
 using Xunit;
 

test/Microsoft.AspNet.Server.Kestrel.FunctionalTests/RequestTests.cs

@@ -8,7 +8,6 @@
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
-using Microsoft.Dnx.Runtime.Infrastructure;
 using Microsoft.Extensions.Configuration;
 using Xunit;
 

test/Microsoft.AspNet.Server.Kestrel.FunctionalTests/ResponseTests.cs

@@ -6,7 +6,6 @@
 using System.Threading.Tasks;
 using Microsoft.AspNet.Builder;
 using Microsoft.AspNet.Hosting;
-using Microsoft.Dnx.Runtime.Infrastructure;
 using Microsoft.Extensions.Configuration;
 using Xunit;
 

test/Microsoft.AspNet.Server.Kestrel.FunctionalTests/ThreadCountTests.cs

@@ -8,7 +8,6 @@
 using Microsoft.AspNet.Hosting;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Features;
-using Microsoft.Dnx.Runtime.Infrastructure;
 using Microsoft.Extensions.Configuration;
 using Xunit;