成功回傳TRUE失敗回傳FALSE。
ldap_free_result() frees up the
memory allocated internally to store the result and pointed
by the result_identifier.
All result memory will be automatically freed when the script
terminates.
Typically all the memory allocated for the ldap result
gets freed at the end of the script. In case the script is
making successive searches which return large result sets, ldap_free_result() could be called to
keep the runtime memory usage by the script low.