Refs #3929 Forum; raise NotFound when trying to download a BFile that has no uploaded content

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/naaya.content.bfile@21217 a0171fae-0946-0410-966d-b1775066cd26
Bump egg to development

git-svn-id: https://svn.eionet.europa.eu/repositories/Naaya/trunk/eggs/naaya.content.bfile@21218 a0171fae-0946-0410-966d-b1775066cd26