Fixed an build issue with exceptionless.signed not having the same dependencies

Author: niemyjski

src/Exceptionless.Signed/project.json

@@ -195,7 +195,7 @@
             "dependencies": {
                 "Microsoft.CSharp": "4.0.1-rc2-24027",
                 "Microsoft.Extensions.PlatformAbstractions": "1.0.0-rc2-final",
-                "System.AppDomain": "2.0.8",
+                "System.AppDomain": "2.0.9",
                 "System.Collections": "4.0.11-rc2-24027",
                 "System.Collections.Concurrent": "4.0.12-rc2-24027",
                 "System.ComponentModel.TypeConverter": "4.0.1-rc2-24027",