Updated url to github download

Updated url to github download from "https://github.com/liferay/liferay-docs/tree/master/develop/learning-paths/code/01-beginning-liferay-development/begin-sdk" to "https://github.com/liferay/liferay-docs/tree/master/develop/learning-paths/jsf/code/learning-sdk".

Old url points to 404 page.