ITS#7741 Fix entryDN index lookup

DN notfound is authoritative, don't ignore the result

servers/slapd/back-bdb/filterindex.c

@@ -728,6 +728,10 @@ equality_candidates(
 		if ( ei ) {
 			bdb_cache_entryinfo_unlock( ei );
 		}
+		if ( rc == DB_NOTFOUND ) {
+			BDB_IDL_ZERO( ids );
+			rc = 0;
+		}
 		return rc;
 	}
 

servers/slapd/back-mdb/filterindex.c

@@ -696,6 +696,10 @@ equality_candidates(
 			ids[0] = 1;
 			ids[1] = id;
 		}
+		if ( rc == MDB_NOTFOUND ) {
+			MDB_IDL_ZERO( ids );
+			rc = 0;
+		}
 		return rc;
 	}