eina_value: fix struct type.
eina_value: fix struct type.

 1. consider case where the struct was not set for flush and others;
 2. flush previous struct on pset;
 3. setup the new struct members memory on pset;
 4. always use ops->alloc and ops->free if they are provided;



SVN revision: 67662

turran/eina,gfriloux/eina,gfriloux/eina,turran/eina,turran/eina,gfriloux/eina