Replace -DSLAPD_SCHEMA_COMPAT with -USLAPD_SCHEMA_NOT_COMPAT

servers/slapd/acl.c

servers/slapd/aclparse.c

servers/slapd/attr.c

servers/slapd/ava.c

servers/slapd/back-ldbm/compare.c

servers/slapd/back-ldbm/external.h

servers/slapd/back-ldbm/group.c

servers/slapd/back-ldbm/index.c

servers/slapd/back-ldbm/modify.c

servers/slapd/back-ldbm/tools.c

servers/slapd/backend.c

servers/slapd/config.c

servers/slapd/filter.c

servers/slapd/filterentry.c

servers/slapd/proto-slap.h

servers/slapd/schema.c

servers/slapd/schemaparse.c

servers/slapd/slap.h

servers/slapd/value.c