Anaconda 42.16

• util: correct errors and suppress stderr for common cases (riehecky)
• payload: utilize du command for finding the required disk size in live OS
  (k.koukiou)
• Fix typo in anaconda hints (jstodola)
• doc: Fix bullet list in Wayland migration rel note (jkonecny)
• doc: Add dropped kernel options to Wayland relnote (jkonecny)
• payload: raise exception on non zero exit code from rsync (k.koukiou)