Fix broken registration: missing cur and wronge exc

etiquette/photodb.py

@@ -1061,6 +1061,7 @@ class PDBUserMixin:
 
         (qmarks, bindings) = helpers.binding_filler(constants.SQL_USER_COLUMNS, data)
         query = 'INSERT INTO users VALUES(%s)' % qmarks
+        cur = self.sql.cursor()
         cur.execute(query, bindings)
 
         if commit:

etiquette_site.py

@@ -245,7 +245,7 @@ def post_register():
 
     try:
         user = P.register_user(username, password_1)
-    except EtiquetteException as e:
+    except exceptions.EtiquetteException as e:
         response = {
             'error_type': e.error_type,
             'error_message': e.error_message,