build: skip msi build if WiX is not found

If none of VS2013/VS2015 WiX installs are found on a builder
machine, skip node build and notify user about.

PR-URL: https://github.com/nodejs/node/pull/5220
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>

vcbuild.bat

@@ -145,7 +145,7 @@ if defined msi (
   if not exist "%WIX%\SDK\VS2013" (
     echo Failed to find WiX install for Visual Studio 2013
     echo VS2013 support for WiX is only present starting at version 3.8
-    goto vc-set-2012
+    goto wix-not-found
   )
 )
 if "%VCVARS_VER%" NEQ "120" (