Unable to specify custom LDAP ports

During testing of 11.3 RC2 we ran into the issiu that LDAP will fail with custom ports.

In 11.2. you can specify the port by using the LDAP hostname: LDAP_FQDN:PORT or IP:PORT.
Now it will fail with the following error message:

[EFAULT] ldap_update: [EFAULT] [Errno 8] hostname nor servname provided, or not known