LU-11237 build: delete obsolete slapd-lustre.conf

LU-11237 build: delete obsolete slapd-lustre.conf

Delete the obsolete slapd-lustre.conf file, as it was only used
for LDAP configuration of clients and servers back before
"zero-conf" (MGS+llog) configuration was available.  Also remove
the use of openldap in Makefile.am.

This has been obsolete since Lustre 1.4 or so.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: If99ca0a62a1753ead1b29d217bc2437bd29e0850
Reviewed-on: https://review.whamcloud.com/32989
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>