fix previous commit (addresses ITS#4139)

servers/slapd/back-ldap/extended.c

@@ -137,9 +137,11 @@ retry:
 					NULL, NULL, 0 );
 			if ( rs->sr_matched && rs->sr_matched[ 0 ] == '\0' ) {
 				free( (char *)rs->sr_matched );
+				rs->sr_matched = NULL;
 			}
 			if ( rs->sr_text && rs->sr_text[ 0 ] == '\0' ) {
 				free( (char *)rs->sr_text );
+				rs->sr_text = NULL;
 			}
 			if ( rc == LDAP_SUCCESS ) {
 				if ( rs->sr_err == LDAP_SUCCESS ) {
@@ -177,12 +179,12 @@ retry:
 	/* these have to be freed anyway... */
 	if ( rs->sr_matched ) {
 		free( (char *)rs->sr_matched );
+		rs->sr_matched = NULL;
 	}
 	if ( rs->sr_text ) {
 		free( (char *)rs->sr_text );
+		rs->sr_text = NULL;
 	}
-	rs->sr_matched = NULL;
-	rs->sr_text = NULL;
 
 	if ( lc != NULL ) {
 		ldap_back_release_conn( op, rs, lc );