school: fix http500 for nonaffiliated eduid users

school/views.py

@@ -98,8 +98,10 @@ def login(request):
         co.save()
         g.save()
 
-
+    try:
         affiliation = request.META['affiliation']
+    except KeyError:
+        affiliation = ''
     if affiliation == '':
         affiliation = []
     else: