update_interface function of DistUpgradeViewNonInteractive should be rewritten

[Brian Murray]

As documented in bug 1614576 DistUpgradeViewNonInteractive was failing with a UnicodeDecodeError when writing text to the terminal. While this been worked around by using "errors='ignore'" thereby skipping any failures to decode it would be better if the whole section was rewritten so the text is properly handled.

Barry Warsaw suggested using asyncio.