[fix] Update data_home/mail backup hooks to use ynh_backup helper

data/hooks/backup/17-data_home

@@ -1,10 +1,7 @@
-backup_dir="$1/data/home"
-sudo mkdir -p $backup_dir
-
 . /usr/share/yunohost/helpers
 
 for f in $(find /home/* -type d -prune | awk -F/ '{print $NF}'); do
     if [[ ! "$f" =~ ^yunohost|lost\+found ]]; then
-        ynh_bind_or_cp "/home/$f" "${backup_dir}/$f" 1
+        ynh_backup "/home/$f" "${1}/data/home/$f" 1
     fi
 done

data/hooks/backup/23-data_mail

@@ -1,5 +1,3 @@
-backup_dir="$1/data/mail"
-
 . /usr/share/yunohost/helpers
 
-ynh_bind_or_cp /var/mail $backup_dir 1
+ynh_backup /var/mail "${1}/data/mail" 1