[#728] Add ckan.tracking_enabled to app_globals

The ckan.tracking_enabled ini file setting was being ignored, so page
view tracking wasn't working. Adding ckan.tracking_enabled to
app_globals makes the setting work again.

Fixes #728

ckan/lib/app_globals.py

@@ -57,6 +57,7 @@
     'openid_enabled': {'default': 'true', 'type' : 'bool'},
     'debug': {'default': 'false', 'type' : 'bool'},
     'ckan.debug_supress_header' : {'default': 'false', 'type' : 'bool'},
+    'ckan.tracking_enabled' : {'default': 'false', 'type' : 'bool'},
 
     # int
     'ckan.datasets_per_page': {'default': '20', 'type': 'int'},