Remove useless code in sendNotificationsOnMessage.js
Little refactoring in sendNotificationsOnMessage.js

https://github.com/RocketChat/Rocket.Chat/issues/2035
https://github.com/mcavage/node-ldapjs/issues/349

the ldap refactoring broke older configurations that use a custom filter but use anonymous
access.

Split CA cert into array of strings. This is needed when LDAP server is using certificate which is issued by a CA.

https://nodejs.org/api/tls.html#tls_tls_connect_options_callback

As per NodeJS documentation:

ca: A string, Buffer or array of strings or Buffers of trusted certificates in PEM format. If this is omitted several well known "root" CAs will be used, like VeriSign. These are used to authorize connections.