ldb: Fix search with scope ONE and small result sets

ldb: Fix search with scope ONE and small result sets

This changes the LDB behaviour in the combination of a SCOPE_ONE search and
an index returning less than 10 results.

After b6b5b5fe355fee2a4096e9214831cb88c7a2a4c6 the list->strict flag
became set to false in all cases, rather than being left to the
value set by the caller.

This changes the ldb_kv_index_dn_one() code to force strict
mode on success instead.

Thanks to Marcus Granér, ICEYE Oy for reporting.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14270

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>