Html5 packaging fails on Windows if the user has HOME env var

If user has HOME env var, Html5 packaging creates .emscripten folder within the location specified by HOME, not the expected intermediate location(like C:\Program Files\Epic Games\4.13\Engine\Intermediate\Build\HTML5\.emscripten). This causes packaging to fail.

1. Add HOME env var to the PC, and points to some directory
2. Create a new First Person Project
3. Try to create a html5 package
4. packaging fails with C:\Program Files\Epic Games\4.13\Engine\Intermediate\Build\HTML5\.emscripten not found error

Could not find file: Epic Games\4.12\Engine\Intermediate\Build\HTML5\.emscripten

UE4 Doesn't package nor launch html5

環境変数HOMEが存在すると、HTML5パッケージ化が出来ない