force itools rebuild always (plus readme tweak)

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@34346 20353a03-c40f-0410-a6d1-a30d3c3de9de

buildout/README-2.12.txt

@@ -91,7 +91,8 @@ Please refer to the 'helpers' directory for other distributions.
 Instances
 =========
 
-Note: Instance generation is still a work in progress.
+Note: Instance generation is still a work in progress. In particular, these
+instructions should be much simplified.
 
 After the software components are built, we can generate ERP5 instance
 buildouts from that software.

buildout/software-profiles/erp5-2.12.cfg

@@ -38,7 +38,7 @@ destination = ${itools:source}
 [itools-build]
 recipe = collective.recipe.cmd
 on_install = True
-on_update = False
+on_update = True
 # reference itools-download:destination instead of itools:source to trigger its
 # execution
 cmds =