hash: free internal ring when freeing hash

hash: free internal ring when freeing hash

Since freeing a ring is now possible, then when freeing
a hash table, its internal ring can be freed as well.
Therefore when a new table, with the same name as a previously
freed table, is created, there is no need to look up
the already allocated ring.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>