[PATCH] Add some const-ness to py-cmd.c

[Joel Brobecker]

> Joel> The one transition that worries me is 3.x, and I think this one
> Joel> is going to hurt (at AdaCore).
> 
> It does seem difficult.  Fedora is aiming to switch over for Fedora 22.
> I think we may switch gdb in Fedora 21, though.  The Fedora feature
> proposal is here:
> 
>     https://fedoraproject.org/wiki/Changes/Python_3_as_Default

Same here. We've only discussed it informally, but we had the same
feeling regarding difficulty and timeline.

-- 
Joel