[gnome-photos] properties-dialog: Don't look for the camera if there is none

[Debarshi Ray <debarshir src gnome org>]

commit 096dd796bbb91b4d1a8ce384667db428fb3a2824
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Jan 2 17:45:44 2017 +0100

    properties-dialog: Don't look for the camera if there is none
    
    If the item doesn't have any information about the equipment in its
    metadata, then there is no point looking for it.
    
    The code was surprisingly working so far because the following SPARQL:
      SELECT nfo:manufacturer (<(null)>) nfo:model (<(null)>) WHERE {}
    ... does not return an empty cursor or throw an error, but:
      (null), (null)

 src/photos-properties-dialog.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)
---
diff --git a/src/photos-properties-dialog.c b/src/photos-properties-dialog.c
index fa610f9..0505790 100644
--- a/src/photos-properties-dialog.c
+++ b/src/photos-properties-dialog.c
@@ -367,11 +367,6 @@ photos_properties_dialog_constructed (GObject *object)
     }
 
   equipment = photos_base_item_get_equipment (item);
-  photos_camera_cache_get_camera_async (self->camera_cache,
-                                        equipment,
-                                        self->cancellable,
-                                        photos_properties_dialog_get_camera,
-                                        self);
   if (equipment != 0)
     {
       self->camera_w = gtk_label_new (_("Camera"));
@@ -511,6 +506,15 @@ photos_properties_dialog_constructed (GObject *object)
       g_free (dims_str);
     }
 
+  if (self->camera_w != NULL)
+    {
+      photos_camera_cache_get_camera_async (self->camera_cache,
+                                            equipment,
+                                            self->cancellable,
+                                            photos_properties_dialog_get_camera,
+                                            self);
+    }
+
   if (exposure_time_w != NULL)
     {
       GtkWidget *exposure_time_data;