[FIX] sql_db: revert ee03fc3770

ee03fc3770 introduced a non deterministic bug by choosing an
environment in a set, so the environment is not always the good one.

closes odoo/odoo#36056

Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

odoo/sql_db.py

@@ -413,17 +413,10 @@ class Cursor(object):
     def savepoint(self):
         """context manager entering in a new savepoint"""
         name = uuid.uuid1().hex
-        env = next((e for e in Environment.envs if e.cr is self), None)
-        if env is not None:
-            env['base'].flush()
         self.execute('SAVEPOINT "%s"' % name)
         try:
             yield
-            if env is not None:
-                env['base'].flush()
         except Exception:
-            if env is not None:
-                env.clear()
             self.execute('ROLLBACK TO SAVEPOINT "%s"' % name)
             raise
         else: