LDAP server timeout can cause PHP timeout

If your LDAP server connection fails due to a network timeout, then php timesout.

It is probably a better idea to have the ldap_bind (for that operation) request fail, and then have the module error handling report a connection problem.

PHP 5.3 has an option: LDAP_OPT_NETWORK_TIMEOUT which handles failures. The options is set easily in PHP:
http://bugs.php.net/bug.php?id=42837&edit=1

Integrating this will require using PHP 5.3, as the option is not allowed before then. I do believe that older version of PHP will fail quietly as the option is set using 'ldap_set_option', it may produce a php warning message.

Modifications would include:
1. ldapauth.admin.inc : include form controls and set_variable for the new options ("set a network timeout for ldap connections")
2. LDAPInterface.inc : implement 'ldap_set_option' after connect, before bind (I think.)

You can assign this to me if you'd like me to submit a patch.