[churn] Ignore merge csets Merge changesets attributed a large number of lines to people that didn't actually develop it, but simply merged the code. By ignoring merges, we get a more accurate picture of how much code everyone changed.

abort: Failed to parse .../t/.hg/hgrc
File contains no section headers.
file: .../t/.hg/hgrc, line: 1
'invalid\n'