Remove unused variables from catch

ObservatoryCore/PluginManagement/PluginEventHandler.cs

@@ -116,7 +116,7 @@ namespace Observatory.PluginManagement
             {
                 timer.Start();
             }
-            catch (ObjectDisposedException ode)
+            catch
             {
                 // Not sure why this happens, but I've reproduced it twice in a row after hitting
                 // read-all while also playing (ie. generating journals).

ObservatoryCore/UI/Views/NotificationView.axaml.cs

@@ -232,7 +232,7 @@ namespace Observatory.UI.Views
                     // Cleanup
                     XFixesDestroyRegion((IntPtr)display, region);
                 }
-                catch (DllNotFoundException ignored)
+                catch
                 {
                     // libXfixes is not installed for some reason
                 }