Remove unncessary usings

Author: javiercn

samples/StaticFileSample/project.json

@@ -17,10 +17,7 @@
           "version": "1.0.0-*",
           "type": "platform"
         }
-      },
-      "imports": [
-        "dnxcore50"
-      ]
+      }
     }
   },
   "publishOptions": {
@@ -30,10 +27,7 @@
     ]
   },
   "tools": {
-    "Microsoft.AspNetCore.Server.IISIntegration.Tools": {
-      "version": "1.0.0-*",
-      "imports": "portable-net45+wp80+win8+wpa81+dnxcore50"
-    }
+    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-*"
   },
   "scripts": {
     "postpublish": "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%"