Fix hash.hh for VCXX > 2005.
Fix hash.hh for VCXX > 2005.

	* include/libport/hash.hh: hash namespace is stdext for vcxx>=2005.

Signed-off-by: Matthieu Nottale <73d816bf5a7c98ca49eb19b3fa4036e0ae653e5f@gostai.com>

aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport,aldebaran/libport