[FIX] auth_brute_force: Don't error on migrations

Migrating from v9 will fail as that version doesn't have the 10.0.1.0.0 data structure

auth_brute_force/migrations/10.0.2.0.0/pre-migrate.py

@@ -8,6 +8,10 @@ from psycopg2 import IntegrityError
 def migrate(cr, version):
     if not version:
         return
+    # Don't act when coming from version 9
+    cr.execute("SELECT 1 FROM pg_class WHERE relname = 'res_banned_remote'")
+    if not cr.fetchone():
+        return 
     # Fix typo across DB
     cr.execute(
         """ UPDATE res_authentication_attempt