package/openldap: security bump to version 2.4.50

Security fixes:
 CVE-2020-12243: Fixed slapd to limit depth of nested filters

Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
[yann.morin.1998@free.fr: two spaces in hash file]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>