Bluetooth: don't restrict the length of non numeric PINs

The protocol restriction is only for numeric PINs (passkeys, in bluez
jargon). For passwords, any length is allowed.

https://bugzilla.gnome.org/show_bug.cgi?id=683356

js/ui/status/bluetooth.js

@@ -456,7 +456,10 @@ const PinNotification = new Lang.Class({
 
     _canActivateOkButton: function() {
         // PINs have a fixed length of 6
+        if (this._numeric)
             return this._entry.clutter_text.text.length == 6;
+        else
+            return true;
     },
 
     grabFocus: function(lockTray) {