util._hgexecutable: default to 'hg'
This should make hooks work even if util.set_hgexecutable is not called
(e.g. hgweb.cgi).
Fixes issue625.
#!/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