Add warning when a file parse failed previously
Add warning when a file parse failed previously

- Add db check for zero parsed lines when current log file is found in
  ProcessedFiles table, and log a warning instead of an info message
  informing of a skipped file so that the previous problem is not hidden.
- Change "omitting" to "skipping" for ease of understanding.

stfc/apel,tofu-rocketry/apel,apel/apel,tofu-rocketry/apel,stfc/apel,apel/apel