debugger: disable 'target async' in the ui

No real benefits so far.

Task-number: QTCREATORBUG-4682
Change-Id: Ibb416fed09e4e0210a84a51b2cd71189ac01ffa6
Reviewed-on: http://codereview.qt.nokia.com/631
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/debugger/gdb/gdboptionspage.cpp

@@ -134,6 +134,10 @@ QWidget *GdbOptionsPage::createPage(QWidget *parent)
                    ;
         m_searchKeywords.remove(QLatin1Char('&'));
     }
+
+    // FIXME: Not fully working on the gdb side yet.
+    m_ui->checkBoxTargetAsync->hide();
+
     return w;
 }