fix parsing of scope option in pynslcd


git-svn-id: http://arthurdejong.org/svn/nss-pam-ldapd/nss-pam-ldapd@1916 ef36b2f9-881f-0410-afb5-c4e39611909c
support children search scope for systems that have it

git-svn-id: http://arthurdejong.org/svn/nss-pam-ldapd/nss-pam-ldapd@1917 ef36b2f9-881f-0410-afb5-c4e39611909c