[py3] Decode subprocess stdout in toolsutils.show_diffs()
On Python 3, subprocess' pipes are bytes stream so we must decode them
before printing. Without this change, diff of configuration files (e.g.
all-in-one.conf as displayed upon instance upgrade) will rendered as a
single line on Python 3.
Document: cubicweb-doc
Title: CubicWeb Documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/python-cubicweb-documentation/html/index.html
Files: /usr/share/doc/python-cubicweb-documentation/html/*