[ticket/13096] Add phpbb_ prefix to ldap_escape()

PHPBB3-13096
Merge pull request #2989 from Senky/ticket/13096

[ticket/13096] ldap_escape() added to PHP 5.6.0

* Senky/ticket/13096:
  [ticket/13096] Add phpbb_ prefix to ldap_escape()
Merge branch 'develop-olympus' into develop-ascraeus

* develop-olympus:
  [ticket/13096] Add phpbb_ prefix to ldap_escape()

Conflicts:
	phpBB/includes/auth/auth_ldap.php