Fix stringshare on 64bits platforms.
Fix stringshare on 64bits platforms.

sizeof(Eina_Stringshare_Node) is now 24 bytes on 64bits platforms, but
str[] was pointing to before that, to the 20th byte, causing out of
bounds access.

Adding the padding will cause str[] to use the correct position. It
wastes 4 more bytes, like pre-optimizations, but it's just on big
machines.



SVN revision: 37305

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