main: Close runDialog as necessary on session mode changes

We already do this for looking glass, but it makes even less sense
for the normal run dialog - if a mode sets runDialog to false, the
intention is to not allow executing aribitrary commands.

https://bugzilla.gnome.org/show_bug.cgi?id=708218

js/ui/main.js

@@ -90,8 +90,12 @@ function _sessionUpdated() {
                                   Shell.KeyBindingMode.OVERVIEW,
                                   sessionMode.hasRunDialog ? openRunDialog : null);
 
-    if (!sessionMode.hasRunDialog && lookingGlass)
-        lookingGlass.close();
+    if (!sessionMode.hasRunDialog) {
+        if (runDialog)
+            runDialog.close();
+        if (lookingGlass)
+            lookingGlass.close();
+    }
 }
 
 function start() {