Regression: Fix livechat find departments

[sampaiodiego]

Proposed changes (including videos or screenshots)

This error is happening when visitor is sending the first message:

Exception on find errorClass [Error]: Match error: Failed Match.OneOf, Match.Maybe or Match.Optional validation
    at check (packages/check/match.js:36:17)
    at ns.Collection._getFindOptions (packages/mongo/collection.js:295:7)
    at ns.Collection.find (packages/mongo/collection.js:336:12)
    at BaseDb.find (app/models/server/models/_BaseDb.js:177:21)
    at LivechatDepartment.find (app/models/server/models/_Base.js:106:29)
    at LivechatDepartment.findEnabledWithAgents (app/models/server/models/LivechatDepartment.js:100:15)
    at Object.getRequiredDepartment (app/livechat/server/lib/Livechat.js:125:42)
    at app/livechat/server/lib/Livechat.js:152:29
    at /home/chinello/.meteor/packages/promise/.0.11.2.j40ifr.9pr39++os+web.browser+web.browser.legacy+web.cordova/npm/node_modules/meteor-promise/fiber_pool.js:43:40 {
  path: '',
  sanitizedError: errorClass [Error]: Match failed [400]
      at errorClass.<anonymous> (packages/check/match.js:91:27)
      at new errorClass (packages/meteor.js:655:17)
      at check (packages/check/match.js:36:17)
      at ns.Collection._getFindOptions (packages/mongo/collection.js:295:7)
      at ns.Collection.find (packages/mongo/collection.js:336:12)
      at BaseDb.find (app/models/server/models/_BaseDb.js:177:21)
      at LivechatDepartment.find (app/models/server/models/_Base.js:106:29)
      at LivechatDepartment.findEnabledWithAgents (app/models/server/models/LivechatDepartment.js:100:15)
      at Object.getRequiredDepartment (app/livechat/server/lib/Livechat.js:125:42)
      at app/livechat/server/lib/Livechat.js:152:29
      at /home/chinello/.meteor/packages/promise/.0.11.2.j40ifr.9pr39++os+web.browser+web.browser.legacy+web.cordova/npm/node_modules/meteor-promise/fiber_pool.js:43:40 {
    isClientSafe: true,
    error: 400,
    reason: 'Match failed',
    details: undefined,
    errorType: 'Meteor.Error'
  },
  errorType: 'Match.Error'
} { numAgents: { '$gt': 0 }, enabled: true } null

Issue(s)

Steps to test or reproduce

Further comments