Avoid adding to the changelog executable files added by the second parent.
This was a regression introduced by b51a8138292a.
#!/bin/sh
echo 'raise Exception("bit bucket overflow")' > badext.py
abspath=`pwd`/badext.py
echo '[extensions]' >> $HGRCPATH
echo "gpg =" >> $HGRCPATH
echo "hgext.gpg =" >> $HGRCPATH
echo "badext = $abspath" >> $HGRCPATH
hg -q help help