Don't run tests of Exceptionless.MessagePack.Tests in appveyor.

Author: Edward Meng

appveyor.yml

@@ -34,7 +34,7 @@ before_build:
 build_script:
   - ps: .\build\Build.ps1
   - dotnet build test\Exceptionless.Tests -c Release
-  - dotnet build test\Exceptionless.MessagePack.Tests -c Release
+#  - dotnet build test\Exceptionless.MessagePack.Tests -c Release
 
 #test_script:
 #  - dotnet test test\Exceptionless.Tests\