Don't use shutil backport on py3

Review Request #10047 — Created June 29, 2018 and submitted — Latest diff uploaded

Information

RBTools
release-1.0.x
4ebd931...

Reviewers

On many distributions (including Fedora and RHEL 7), the backports.shutil package doesn't exist for python 3.x because it's meaningless. Instead of unconditionally including it, use the appropriate import for the python version in use.

Submitted this very review using rbt post on python3 with this patch applied.