instead of sudo, use a busybox to chmod

the user is a member of docker group is already a prerequisite

docker_dev_start.py

@@ -267,4 +267,5 @@
         else:
             logging.debug('Creating volume %s', data_volume_name)
             volume = docker_client.create_volume(name=data_volume_name)
+        mount_opts = 'source={},target=/mnt/data'.format(data_volume_name)
         # make sure the permission in the volume are correct
@@ -270,8 +271,7 @@
         # make sure the permission in the volume are correct
-        # TODO replace by something cleaner...
-        mount_point = volume['Mountpoint']
-        call(['sudo', 'chmod', '777', mount_point])
-        options.append('source={},target=/mnt/data'.format(data_volume_name))
+        # TODO replace by something cleaner if possible
+        call(['docker', 'run', '--rm', '--mount', mount_opts, 'busybox', 'chmod', '777', '/mnt/data'])
+        options.append(mount_opts)
         arg.append('--data-dir /mnt/data')
     else:
         logging.debug('No data volume for this odoo version')