Corregir error "Could not get content for X defined in bundle 'X'" en Odoo 8.0

Problema

Hoy tras actualizar mi Odoo, me he encontrado estos errores al entrar:

Could not get content for /website/static/src/css/bootswatch/spacelab.min.css defined in bundle 'website.assets_frontend'.
Could not get content for /website/static/src/css/bootswatch/spacelab.fix.css defined in bundle 'website.assets_frontend'.
Could not get content for /website/static/src/css/website.css defined in bundle 'website.assets_frontend'.
Could not get content for /website_mail/static/src/css/website_mail.css defined in bundle 'website.assets_frontend'.
Could not get content for /website_blog/static/src/css/website_blog.css defined in bundle 'website.assets_frontend'.

Un error un tanto extraño.

Diagnóstico

Revisando los registros, encontré este error:

ERROR ? werkzeug: Error on request:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 177, in run_wsgi
    execute(self.server.app)
  File "/usr/lib/python2.7/site-packages/werkzeug/serving.py", line 165, in execute
    application_iter = app(environ, start_response)
  File "/usr/lib/python2.7/site-packages/openerp/service/server.py", line 281, in app
    return self.app(e, s)
  File "/usr/lib/python2.7/site-packages/openerp/service/wsgi_server.py", line 216, in application
    return application_unproxied(environ, start_response)
  File "/usr/lib/python2.7/site-packages/openerp/service/wsgi_server.py", line 202, in application_unproxied
    result = handler(environ, start_response)
  File "/usr/lib/python2.7/site-packages/openerp/http.py", line 1274, in __call__
    self.load_addons()
  File "/usr/lib/python2.7/site-packages/openerp/http.py", line 1293, in load_addons
    m = __import__('openerp.addons.' + module)
  File "/usr/lib/python2.7/site-packages/openerp/modules/module.py", line 79, in load_module
    mod = imp.load_module('openerp.addons.' + module_part, f, path, descr)
  File "/opt/odoo/extra-addons/l10n-spain/account_balance_reporting_xls/__init__.py", line 8, in <module>
    from . import report
  File "/opt/odoo/extra-addons/l10n-spain/account_balance_reporting_xls/report/__init__.py", line 7, in <module>
    from . import reporting_xls
  File "/opt/odoo/extra-addons/l10n-spain/account_balance_reporting_xls/report/reporting_xls.py", line 5, in <module>
    import xlwt
ImportError: No module named xlwt

Al parecer, tras actualizar los módulos comunitarios del paquete l10n-spain, se introdujo una nueva dependencia (xlwt) que no ha quedado satisfecha. Como ese módulo no se ha cargado, el proceso se ha interrumpido y no ha llegado a cargar el módulo website, que es en el que se encuentran los CSS que me daban error al principio.

Solución

# yum install python-xlwt

Evidentemente, dependiendo de cuál sea el fallo en tu Odoo, deberás instalar un paquete u otro. Sigue mis pasos y llegarás en seguida al problema.

Por ejemplo, en mi caso, además de esto tuve que añadir el repositorio comunitario reporting-engine.