Back out giant lock code, needs more work

servers/slapd/back-ldbm/add.c

servers/slapd/back-ldbm/back-ldbm.h

servers/slapd/back-ldbm/bind.c

servers/slapd/back-ldbm/compare.c

servers/slapd/back-ldbm/delete.c

servers/slapd/back-ldbm/entry.c

servers/slapd/back-ldbm/init.c

servers/slapd/back-ldbm/modify.c

servers/slapd/back-ldbm/modrdn.c

servers/slapd/back-ldbm/nextid.c

servers/slapd/back-ldbm/passwd.c

servers/slapd/back-ldbm/referral.c

servers/slapd/back-ldbm/search.c