Add debugging code for overlays.

static/js/overlays.js

@@ -44,6 +44,8 @@ exports.open_overlay = function (opts) {
         return;
     }
 
+    blueslip.debug('open overlay: ' + opts.name);
+
     // Our overlays are kind of crufty...we have an HTML id
     // attribute for them and then a data-overlay attribute for
     // them.  Make sure they match.
@@ -68,6 +70,13 @@ exports.close_overlay = function (name) {
         return;
     }
 
+    if (name === undefined) {
+        blueslip.error('Undefined name was passed into close_overlay');
+        return;
+    }
+
+    blueslip.debug('close overlay: ' + name);
+
     active_overlay.removeClass("show");
 
     if (!close_handler) {