Block / Remove reaction R10221

[sulheim]

The activity of phosphogluconate dehydrogenase in S. coelicolor with NAD and NADP is tested by Coze et al., 2013. They find that this enzyme is strictly NADP dependent, so I think we can remove R10221.

I hereby confirm that:

• [x] This problem persists in the master branch of the repository
• [x] A similar issue does not already exist
• [x] I've considered asking this first in the Gitter chat room