Update references

Microsoft.Framework.NotNullAttribute.Internal =>
Microsoft.Framework.NotNullAttribute.Sources

Author: troydai

src/Microsoft.AspNet.Localization/project.json

@@ -6,7 +6,7 @@
     "Microsoft.AspNet.Http.Extensions": "1.0.0-*",
     "Microsoft.Framework.Globalization.CultureInfoCache": "1.0.0-*",
     "Microsoft.Framework.Localization.Abstractions": "1.0.0-*",
-    "Microsoft.Framework.NotNullAttribute.Internal": { "type": "build", "version": "1.0.0-*" }
+    "Microsoft.Framework.NotNullAttribute.Sources": { "type": "build", "version": "1.0.0-*" }
   },
 
   "frameworks": {

src/Microsoft.Framework.Localization.Abstractions/project.json

@@ -3,7 +3,7 @@
   "description": "Abstractions of application localization services.",
 
   "dependencies": {
-    "Microsoft.Framework.NotNullAttribute.Internal": { "type": "build", "version": "1.0.0-*" }
+    "Microsoft.Framework.NotNullAttribute.Sources": { "type": "build", "version": "1.0.0-*" }
   },
 
   "frameworks": {

src/Microsoft.Framework.Localization/project.json

@@ -5,7 +5,7 @@
   "dependencies": {
     "Microsoft.Framework.DependencyInjection.Abstractions": "1.0.0-*",
     "Microsoft.Framework.Localization.Abstractions": "1.0.0-*",
-    "Microsoft.Framework.NotNullAttribute.Internal": { "type": "build", "version": "1.0.0-*" },
+    "Microsoft.Framework.NotNullAttribute.Sources": { "type": "build", "version": "1.0.0-*" },
     "Microsoft.Framework.Runtime.Abstractions": "1.0.0-*",
     "System.Resources.ReaderWriter": "4.0.0-*"
   },