borg-client: replace mysqldump with xtrabackup

roles/borg-client/templates/backup-mysql.sh.j2

@@ -3,12 +3,6 @@
 mysql_opts="--defaults-file={{mysql_backup_defaults}}"
 backupdir="{{mysql_backup_dir}}"
 
-for db in $(mysql $mysql_opts -e 'show databases' -s --skip-column-names); do
-        if [[ $db != "information_schema" && $db != "performance_schema" ]]; then
-                mysqldump $mysql_opts "$db" --quick --create-options --disable-keys --add-locks --add-drop-table --lock-tables --complete-insert --skip-extended-insert | gzip > "$backupdir/$db.sql.gz"
-        fi
-done
-
-[[ ! -d "$backupdir/xtrabackup" ]] && mkdir -p "$backupdir/xtrabackup"
-rm -rf "$backupdir/xtrabackup/"*
-xtrabackup $mysql_opts --backup --target-dir="$backupdir/xtrabackup"
+[[ ! -d "$backupdir" ]] && mkdir -p "$backupdir"
+rm -rf "$backupdir"/*
+xtrabackup $mysql_opts --backup --target-dir="$backupdir"