Update views.py
Update views.py

Mimetype changed to content_type in django 1.7, fix in rosett views.
fladi/django-rosetta,dchoruzy/django-rosetta,BakanovKirill/django-rosetta,mbi/django-rosetta,fladi/django-rosetta,adamjforster/django-rosetta,mbi/django-rosetta,BakanovKirill/django-rosetta,BakanovKirill/django-rosetta,dchoruzy/django-rosetta,dchoruzy/django-rosetta,adamjforster/django-rosetta,mbi/django-rosetta,adamjforster/django-rosetta,fladi/django-rosetta,mbi/django-rosetta