Don't use sed -r; instead use old-style regexp
Rev
d895158fe8af introduced some sed -r tests, but -r is only available on GNU
sed, while BSD sed uses -E. Better to use old-style regular expressions, that
way the tests work on all sed variants.
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "hgk=" >> $HGRCPATH
hg init repo
cd repo
echo a > a
hg ci -Am adda
hg debug-cat-file commit 0