Importing `cElementTree` has been deprecated since Python 3.3 -
importing `ElementTree` automatically uses the fastest
implementation available - and is finally removed in Python 3.9.
Importing cElementTree directly (not as part of xml) is an even
older relic, it's for Ye Time Before ElementTree Was Added To
Python and it was instead an external module...which was before
Python 2.5.
We still need to work with Python 2.7 for now, so we use a try/
except to handle both 2.7 and 3.9 cases. Also, let's not repeat
this import 12 times in one file for some reason.
Signed-off-by: Adam Williamson <awilliam@redhat.com>
