etw,build: always generate .rc and .h files

We can assume the Windows SDK is installed, hence the intermediate
files generated from manifest should not be part of the source tree.
This also fixes incorrect detection of ctrpp.exe, that should be in
the path.

PR-URL: https://github.com/nodejs/node/pull/5657


Reviewed-By: Alexis Campailla <orangemocha@nodejs.org>