Fix digdelv test - 9.16
The yamlget.py file was changed in !3311 (merged) as part of making the python code pylint and flake8 compliant. This omitted setting 'item' to 'item[key]' which caused the digdelv yaml tests to fail.
Also, the pretty printing is not really necessary, so remove the "if key not in item; print error" logic.
(cherry picked from commit 464d0417)