Otherwise you get "Access denied: watch IPN bus access denied, must
set ipn.NotifyNoPrivateKeys when not running as admin/root or
operator".
This lets a non-operator at least start the app and see the status, even
if they can't change everything. (the web UI is unaffected by operator)
A future change can add a LocalAPI call to check permissions and guide
people through adding a user as an operator (perhaps the web client
can do that?)
Updates #1708
Change-Id: I699e035a251b4ebe14385102d5e7a2993424c4b7
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>