Disable ok/cancel buttons if updating when opening update dialog.

Fixes issue 4451

Change-Id: I81ed6cebbdd017eae8d428ed3395b19c272de9c9
Reviewed-on: http://gerrit.dmdirc.com/1499
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

src/com/dmdirc/addons/ui_swing/dialogs/updater/SwingUpdaterDialog.java

@@ -125,6 +125,10 @@ public final class SwingUpdaterDialog extends StandardDialog implements
                 me = new SwingUpdaterDialog(updates, mainFrame);
             } else {
                 ((UpdateTableModel) me.table.getModel()).setUpdates(updates);
+                if (UpdateChecker.getStatus() == STATE.UPDATING) {
+                    me.getOkButton().setEnabled(false);
+                    me.getCancelButton().setVisible(false);
+                }
             }
         }