Bug with uploading primary thesis file

[dndeli]

On the view thesis screen, if you try to upload a primary file that is not a pdf, you get taken to a screen that says the primary file must be a PDF and from that screen if you try to upload a PDF, you get taken back to the view thesis screen and the file is not uploaded.

[asadaqain]

is related to #66 and possibly also #64.

[dndeli]

done and merged to develop