Both are used by `./configure` internally, not by curl C code.
CMake adds `NEED_LBER_H` to `CURL_TEST_DEFINES`, which is used by
`curl_internal_test()`, but there is no LDAP-related test made with that
call.
Thus, stop detecting and publishing these from CMake.
`NEED_LBER_H` added in 7320e53d9e.
`HAVE_LDAP_H` added in 4c5307b456 (initial CMake commit).
Closes#14690