use a more reliable way to find what are the new changesets on pull/unbundle
The number of csets and the hooks where wrong (negative number of csets) when
we unbundled a bundle which contains csets we already had.
Remove unused variables.
abort: Failed to parse .../t/.hg/hgrc
File contains no section headers.
file: .../t/.hg/hgrc, line: 1
'invalid\n'