[Dbix-class] Cat Model DBIC Schema fails test if *optional* prereq isn't installed

[Toby Corkindale]

Toby Corkindale wrote:
> Hi,
> Catalyst::Model::DBIC::Schema lists Catalyst::Devel as an *optional* 
> dependency.
> 
> However if you do not have Catalyst::Helper installed (via 
> Catalyst::Devel) then C-M-DBIC-Schema fails its unit tests and won't 
> install via CPAN.

Fix committed to trunk.

Cheers,
Toby