Revert "[Venom] Backup and restore: Remove public user the right way"…

… is failing because PUBLIC does not have HOST.

Previous way still working.

This reverts commit a0e51cd.

t/venom/test_suites/backup_db_and_restore/00_backup_db_and_restore.yml

@@ -23,7 +23,7 @@ testcases:
 - name: remove PUBLIC user from mysql.user
   steps:
   - type: exec
-    script: "mysql -e'DROP USER IF EXISTS PUBLIC;'"
+    script: "mysql -e'DELETE FROM mysql.user WHERE User=\"PUBLIC\"';"
 
 - name: create exportable backup
   steps: