Fixed using the default icon when the icon isn't found

usr/lib/linuxmint/mintMenu/plugins/easybuttons.py

@@ -76,10 +76,19 @@ class IconManager(GObject.GObject):
                 image = Gtk.Image.new_from_pixbuf(pb)
             elif canSetByName:                
                 image = Gtk.Image()
+                icon_found = False
+                for theme in self.themes:
+                    if theme.has_icon( realIconName ):
+                        icon_found = True
+                        break
+
+                if icon_found:
                     image.set_from_icon_name(realIconName, Gtk.IconSize.DND)
                     image.set_pixel_size(iconSize)
                 else:
                     image = None
+            else:
+                image = None
 
             return image
         except Exception, e:
@@ -178,7 +187,7 @@ class easyButton( Gtk.Button ):
             return None
 
         icon = iconManager.getIcon( self.iconName, iconSize )
-        if not icon:
+        if icon is None:           
             icon = iconManager.getIcon( "application-default-icon", iconSize )
 
         return icon