MDEV-21951: mariabackup SST fail if data-directory have lost+found directory

To fix this, it is necessary to add an option to exclude the
database with the name "lost+found" from processing (the database
name will be checked by the check_if_skip_database_by_path() or
by the check_if_skip_database() function, and as a result
"lost+found" will be skipped).

In addition, it is necessary to slightly modify the verification
logic in the check_if_skip_database() function.

extra/mariabackup/xtrabackup.cc

@@ -2270,7 +2270,7 @@ check_if_skip_database(
 	if (databases_exclude_hash &&
 		find_filter_in_hashtable(name, databases_exclude_hash,
 					 &database) &&
-		!database->has_tables) {
+		(!database->has_tables || !databases_include_hash)) {
 		/* Database is found and there are no tables specified,
 		   skip entire db. */
 		return DATABASE_SKIP;

scripts/wsrep_sst_mariabackup.sh

@@ -699,9 +699,11 @@ if ${INNOBACKUPEX_BIN} /tmp --help 2>/dev/null | grep -q -- '--version-check'; t
     disver="--no-version-check"
 fi
 
+iopts+=" --databases-exclude=\"lost+found\""
+
 if [[ ${FORCE_FTWRL:-0} -eq 1 ]];then 
     wsrep_log_info "Forcing FTWRL due to environment variable FORCE_FTWRL equal to $FORCE_FTWRL"
-    iopts+=" --no-backup-locks "
+    iopts+=" --no-backup-locks"
 fi
 
 INNOEXTRA=$WSREP_SST_OPT_MYSQLD