Exception on _bulk_docs

[clochix]

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[2015-12-01 15:04:30:395] ^[[31merror^[[39m - app:error | Cannot read property 'length' of undefined
[2015-12-01 15:04:30:399] ^[[31merror^[[39m - app:error | TypeError: Cannot read property 'length' of undefined
    at Object.async.each (/usr/local/cozy/apps/data-system/node_modules/async/lib/async.js:106:17)
    at Object.module.exports.checkPermissionsPostReplication [as handle] (/usr/local/cozy/apps/data-system/build/server/middlewares/utils.js:75:18)
    at next_layer (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/route.js:103:13)
    at Route.dispatch (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/route.js:107:5)
    at /usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:213:24
    at Function.proto.process_params (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:284:12)
    at next (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:207:19)
    at next (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:182:38)
    at next (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:182:38)
    at next (/usr/local/cozy/apps/data-system/node_modules/americano/node_modules/express/lib/router/index.js:182:38)