remove outdated runtime Information scala home

Author: witgo <witgo@qq.com>

Closes #728 from witgo/scala_home and squashes the following commits:

cdfd8be [witgo] Merge branch 'master' of https://github.com/apache/spark into scala_home
fac094a [witgo] remove outdated runtime Information scala home
(cherry picked from commit 6bee01dd04ef73c6b829110ebcdd622d521ea8ff)

Signed-off-by: Patrick Wendell <pwendell@gmail.com>