Forms must now always specify include or exclude fields

So for those forms that should have everything in them (and we don't
have a lot of those), set exclude=() to remove the error.

pgweb/account/admin.py

@@ -11,6 +11,7 @@ from models import CommunityAuthSite
 class CommunityAuthSiteAdminForm(forms.ModelForm):
 	class Meta:
 		model = CommunityAuthSite
+		exclude = ()
 
 	def clean_cryptkey(self):
 		x = None

pgweb/downloads/admin.py

@@ -33,6 +33,7 @@ duplicate_stackbuilderapp.short_description = "Duplicate application"
 class StackBuilderAppAdminForm(forms.ModelForm):
 	class Meta:
 		model = StackBuilderApp
+		exclude = ()
 
 	def clean_textid(self):
 		if not re.match('^[a-z0-9_]*$', self.cleaned_data['textid']):

pgweb/events/admin.py

@@ -15,6 +15,7 @@ approve_event.short_description = 'Approve event'
 class EventAdminForm(forms.ModelForm):
 	class Meta:
 		model = Event
+		exclude = ()
 
 	def clean(self):
 		cleaned_data = super(EventAdminForm, self).clean()