Remove LDAP_TLS_CA_CRT_FILENAME environment

[kopax]

LDAP_TLS_CA_CRT_FILENAME: Ldap ssl CA certificate filename. Defaults to ca.crt

TLSCACertificateFile is just for validating client certificates, we may not want to provide it in 99% of user case.

Having it with a default value can lead to a potential and unsafe configuration where the server provides the full chain.

I suggest that we remove it by default and just add this to cn=config only if it set ?

[Jyrno42]

Might also make sense to default LDAP_TLS_VERIFY_CLIENT: never when LDAP_TLS_CA_CRT_FILENAME is not set.