Revert "Revert add warning when a parse failed previously"

This reverts commit b43b0c9554129080c5e6693ddd63a223f761dd27.
Improve parser log output

- Add initialization of 'unparsed' to False otherwise the 'elif unparsed'
  might have thrown a wobbly if it wasn't assigned.
- Change unparsed log message from WARN to INFO as only the initial
  failure to parse should be a WARN and INFO is consistent with other
  skipping messages.
- Change messages to be more consistent with surrounding messages in that
  they start with describing the action being performed rather than
  printing the filename.