Code review comment for lp://staging/~roignac/apport/bugpattern-check_for_duplicates

I'm leaving this as non-optional as I found the duplicate checking useful as it allowed me to expand a bug pattern. I did make some minor changes to your branch also.

I removed sys.exit from match_bug so it'll keep checking other duplicates.

Because the tags of a bug report are a list you don't really need to iterate over them.
  if 'apport-crash' in bug.tags:

And using total_size wasn't really necessary. This was sufficient:
  if bug.duplicates: