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.
#!/bin/sh
mkdir a
cd a
hg init
echo foo > b
hg add b
hg ci -m "b" -d "1000000 0"
chmod -w .hg
cd ..
hg clone a b
chmod +w a/.hg # let test clean up
cd b
hg verify