Proper wrapper for evas_hash around eina_hash.

Proper wrapper for evas_hash around eina_hash.

Eina hash api must get non NULL pointer allocated with
eina_hash_new(), but Evas hash started with NULL and would allocate
and destroy the hash as required by operations.

To do a proper wrapper we must ensure we don't call Eina hash API with
NULL, we must handle that outside Eina.

PLEASE do not remove this code again (it's the second time I add it),
this is the correct approach. Other than that is going after evas_hash
usage and converting directly to eina_hash.

git-svn-id: http://svn.enlightenment.org/svn/e/trunk/evas@38091 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33