SchemaShell --name and --file params priority fix.

Corrects the two issues identified by #4174 and CakeDC/migrations#183.

I don't currently have the proper test environment set up to run the core test suite locally, so I'm going to let Travis check things for me. I wouldn't be surprised if there is a test to fix somewhere.
It may be missing from the README but it's in the CONTRIBUTING file:
https://github.com/cakephp/cakephp/blob/master/CONTRIBUTING.md

And yes, there are most probably other files not 100 % styled correctly :laughing: 
So, why don't you just take CakeSchema and fix it?
One file at a time?
One file less on the list?
You can do it!