Update ruby-ldap to 0.9.16.

Fri Sep  6 07:04:07 UTC 2013 Alexey Chebotar <alexey.chebotar@gmail.com>
  * Version 0.9.16
  * Fixed undefined method 'each' in LDAP::LDIF.mods_to_ldif (GH-26).
    Thanks to Francesco Malvezzi.

Thu Aug 29 10:18:48 UTC 2013 Alexey Chebotar <alexey.chebotar@gmail.com>
  * Version 0.9.15
  * Accept nil for new_parent_dn for rename. Thanks to Kouhei Sutou.

Wed Aug 28 13:21:53 UTC 2013 Alexey Chebotar <alexey.chebotar@gmail.com>
  * Version 0.9.14
  * Fixed option parsing bug for LDAP::Conn.sasl_bind. Thanks to Brian Leake.
  * Added possibility to use :nocanon option in rb_ldap_conn_sasl_bind.
    See ldap_set_option(3) for more information. Thanks to Brian Leake.
  * Added function conn.rename(dn, new_rdn, new_parent_dn, delete_old_rdn, sctrls, cctrls)  => self
    Modify the RDN of the entry with DN, dn, giving it the new RDN in parent new_parent_dn,
    new_rdn. If delete_old_rdn is true, the old RDN value will be deleted from the entry.
    Thanks to Marek Veber.
  * Added option LDAP_OPT_NETWORK_TIMEOUT for openLDAP. Thanks to David Campbell.
  * Fixed build error with GCC 4.8.1. Thanks to Kouhei Sutou.
  * Add missing ldap_raname_s() function availability check. Thanks to Kouhei Sutou.
Updated databases/ruby-ldap to 0.9.16