Don't show Profile.api_key in admin.

hc/accounts/admin.py

@@ -19,7 +19,7 @@ class Fieldset:
 
 class ProfileFieldset(Fieldset):
     name = "User Profile"
-    fields = ("email", "api_key", "current_team", "reports_allowed",
+    fields = ("email", "current_team", "reports_allowed",
               "next_report_date", "nag_period", "next_nag_date",
               "token", "sort")