Fix build and react to update CoreCLR packages

aspnet/Coherence#97

Author: JunTaoLuo

samples/Content.Upload.Multipart/project.json

@@ -18,7 +18,7 @@
           "version": "1.0.0-*",
           "type": "platform"
         },
-        "System.Net.Http": "4.0.1-*"
+        "System.Net.Http": "4.1.0-*"
       },
       "imports": [
         "dnxcore50"

samples/Microsoft.AspNetCore.Mvc.TagHelpers.Localization/project.json

@@ -16,7 +16,7 @@
   },
   "frameworks": {
     "net451": {},
-    "netstandard1.5": {
+    "netstandard1.6": {
       "dependencies": {
         "NETStandard.Library": "1.5.0-*"
       },