We have uploaded a logo in the CP, but the CP Login page still has the craftcms logo under the login box. Perhaps a config setting to remove this that I don't know about?
As of Craft 2.5, by default you will see your Site Name in plain text above the login form, and a light Craft CMS logo below it. If you have Craft Client/Pro and upload a custom Login Page Logo from Settings → General, the plain text Site Name will get replaced with that logo, but the Craft CMS logo will remain.
The Login Page Logo was never meant to be used to white-label the CMS - even pre-2.5 if you uploaded a custom logo, there would still be Craft and P&T references in the CP footer (which hasn’t changed).