[Ada] gnatname creates backup copy of project file

[Arnaud Charlet]

Another important change was done in this commit, I've updated the changelog
accordingly:

        (Ada_Version_Default): Switch to Ada 2012 by default.

Since Ada 2012 is the new Ada standard, GNAT is switched to Ada 2012 instead of
Ada 2005 by default.

> Index: opt.ads
> ===================================================================
> 
> --- opt.ads	(revision 197743)
> +++ opt.ads	(working copy)
> @@ -119,14 +119,11 @@
>     --  Think twice before using "="; Ada_Version >= Ada_2012 is more likely
>     --  what you want, because it will apply to future versions of the
>     language.
>  
> -   Ada_Version_Default : constant Ada_Version_Type := Ada_2005;
> +   Ada_Version_Default : constant Ada_Version_Type := Ada_2012;
>     pragma Warnings (Off, Ada_Version_Default);
>     --  GNAT
>     --  Default Ada version if no switch given. The Warnings off is to kill
>     --  constant condition warnings.