It is not a Hijacker. Google Drive is a cloud storage app which is used by millions including myself. When you installed Avast you had the option to not install Google Drive by unticking the check mark. You must have missed this. Just uninstall it. I love how people complain about Google but yet Google is the first place they go when searching for something online. I use everything Google. I even own a Chromebook.

http://www.google.com/drive/about.html?authuser=0