Close connection when listing or testing PostgreSQL databases

Closes #13441
(grafted from 18a811563d659b025b09973157f9d90a7dea8e6f)

--HG--
branch : 7.0

trytond/trytond/backend/postgresql/database.py

@@ -346,7 +346,7 @@ class Database(DatabaseInterface):
                         'Test failed for "%s"', db_name, exc_info=True)
                     continue
         finally:
-            self.put_connection(connection)
+            self.put_connection(connection, close=True)
 
         self.__class__._list_cache[hostname] = res
         self.__class__._list_cache_timestamp[hostname] = now
@@ -391,7 +391,7 @@ class Database(DatabaseInterface):
         try:
             return self._test(connection, hostname=hostname)
         finally:
-            self.put_connection(connection)
+            self.put_connection(connection, close=True)
 
     @classmethod
     def _test(cls, connection, hostname=None):