Import LDAP Users


**Observed Behavior:
I can login success with LDAP authorization. But I can’t Import LDAP Users.

**Expected Behavior:
I can Import LDAP Users.

**Phabricator Version: (stable) Promote 2018 week 50
Ubuntu 18.04, php 7.2.10, MySQL Ver 14.14 Distrib 5.7.24.

Reproduction Steps:
I use “cn=Manager,dc=example,dc=com” LDAP username
and “secret” password, but error such as follow:

Unhandled Exception (“PhutilAuthCredentialException”)

Use same user and password, it can login by phpLDAPAdmin.