Fix ISP database version (should be a float, not a string)

coin/isp_database/models.py

@@ -9,7 +9,7 @@ from coin.members.models import count_active_members
 from coin.offers.models import count_active_subscriptions
 
 # API version, see http://db.ffdn.org/format
-API_VERSION = "0.1"
+API_VERSION = 0.1
 
 TECHNOLOGIES = (('ftth', 'FTTH'),
                 ('dsl', '*DSL'),