Add autorelease pools needed by Qt Creator.

With these Qt Creator startup is now warning-free
on 10.6.

Change-Id: Ie29d360611c0e516258920163e4e94d174217299
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qcocoamenu.mm

@@ -386,6 +386,8 @@ QList<QCocoaMenuItem *> QCocoaMenu::merged() const
 
 void QCocoaMenu::syncModalState(bool modal)
 {
+    QCocoaAutoReleasePool pool;
+
     if (!m_enabled)
         modal = true;
 

src/plugins/platforms/cocoa/qcocoamenubar.mm

@@ -114,6 +114,8 @@ void QCocoaMenuBar::insertMenu(QPlatformMenu *platformMenu, QPlatformMenu *befor
 
 void QCocoaMenuBar::removeMenu(QPlatformMenu *platformMenu)
 {
+    QCocoaAutoReleasePool pool;
+
     QCocoaMenu *menu = static_cast<QCocoaMenu *>(platformMenu);
     if (!m_menus.contains(menu)) {
         qWarning() << Q_FUNC_INFO << "Trying to remove a menu that does not belong to the menubar";