define and export an _nss_ldap_version symbol (3155cdf and 11283a5 from 0.9)

git-svn-id: http://arthurdejong.org/svn/nss-pam-ldapd/nss-pam-ldapd-0.8@1945 ef36b2f9-881f-0410-afb5-c4e39611909c