Remove the SITE_ROOT settings variable and use Django's MEDIA_ROOT instead.

By default MEDIA_ROOT will point to a new 'media' inside Mayan's main directory.

mayan/apps/installation/classes.py

@@ -120,7 +120,6 @@ class VirtualEnv(object):
             yield self.extract_dependency(item)
 
     def __init__(self):
-        self.requirements_file_path = os.path.join(settings.SITE_ROOT, 'requirements', 'production.txt')
         if not PIP:
             raise PIPNotFound