manage.py loaddata crashes with postgres when filling id column of cms_placeholder

[fp4code]

See Arkestra #122 evildmp/Arkestra#122

When the database used is PostgreSQL, the command "manage.py loaddata example_database.json" crashes if the file "example_database.json" contains the block
{
"pk": 1,
"model": "cms.placeholder",
"fields": {
"slot": "body",
"default_width": null
}
},
The crash occurs in the the method Page.rescan_placeholders() (file cms/models/pagemodel.py) because it fills an autoindexed row with an index not taking into account the already filled rows. The problem is clearly decribed here:
http://jesiah.net/post/23173834683/postgresql-primary-key-syncing-issues
and a possible workaround is to insert:
from django.db import connection
cursor = connection.cursor()
cursor.execute("SELECT setval('cms_placeholder_id_seq', (SELECT MAX(id) FROM cms_placeholder)+1)")
But a better way can be certainly found.

[yakky]

Which version of django CMS are you using?

[fp4code]

I'am using an old one: django-cms==2.3.5, as required by Arkestra.
I will do tests with newer versions.

[yakky]

It should be fixed in 2.3.8
@evildmp very little has changed from 2.3.5 to 2.3.8, an upgrade should be feasible, right?

[fp4code]

Sorry, for not for not noticing issue #1031 and commit 00aada0:
"Don't rescan_placeholders when loading fixtures, Fixes #1031".