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.



git-svn-id: a6113611d365f0fc061992be0d1d0b451b434026@37305 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

OpenInkpot-archive/iplinux-eina,jordemort/eina,OpenInkpot-archive/iplinux-eina,jordemort/eina,jordemort/eina,OpenInkpot-archive/iplinux-eina