Just calling vcvarsall.bat w/o any args, it uses latest sdk version
on current windows when it sets env vars like WindowsSDKVer.
It fetches latest installed version from registry.
If we installed 10.0.18362, we can see WindowsSDKVer is set in
hammer-brave.bat by echo.
So far, it was ok but omaha build is failed with 10.0.18362.
Since C77, 18362 became as required SDK version. So, omaha build will
fail w/o this commit.
10.0.10586 is sdk requirement for our forked omaha version.