Add debugging information.

Sometimes .git disappears, and bt5 and product/ERP5/bootstrap changes
permission. Thanks to listing directory contents it will allow to know if
state of directory is correct before git pull.

; are used in order to allow to progress in case of issue, as ls shall not
generate part installation error.

stack/erp5.cfg

@@ -229,7 +229,7 @@ repository = http://git.erp5.org/repos/erp5.git
 branch = master
 revision =
 command = ${git:location}/bin/git clone --quiet --branch ${:branch} ${:repository} ${:location} && if [ -n "${:revision}" ]; then cd ${:location} && ${git:location}/bin/git reset --quiet --hard ${:revision} ; fi
-update-command = cd ${:location} && ${git:location}/bin/git pull --quiet && if [ -n "${:revision}" ]; then cd ${:location} && ${git:location}/bin/git reset --quiet --hard ${:revision} ; fi
+update-command = ls -la ${:location} ; ls -ld ${:location}/product/ERP5/bootstrap ; cd ${:location} && ${git:location}/bin/git pull --quiet && if [ -n "${:revision}" ]; then cd ${:location} && ${git:location}/bin/git reset --quiet --hard ${:revision} ; fi
 
 [products]
 # XXX: ERP5 related products are not defined as python distributions, so it is