Do not crash on some animation changes

Do not crash on some animation changes

stop() might end up deleting the animationjob object so wrap
the call with a RETURN_IF_DELETED

Fixes valgrind complaining
==18380== Invalid read of size 1
==18380==    at 0x5530B24: QAbstractAnimationJob::setCurrentTime(int) (in /home/tsdgeos/qt5/qtdeclarative/lib/libQt5Qml.so.5.0.0)
==18380==    by 0x5530BDE: QQmlAnimationTimer::updateAnimationsTime(long long) (in /home/tsdgeos/qt5/qtdeclarative/lib/libQt5Qml.so.5.0.0)
==18380==    by 0x65C05DC: QUnifiedTimer::updateAnimationTimers(long long) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Core.so.5.0.0)
==18380==    by 0x65C10E3: QAnimationDriver::advanceAnimation(long long) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Core.so.5.0.0)
==18380==    by 0x5047DB9: QQuickRenderThreadSingleContextWindowManager::event(QEvent*) (qquickthreadedwindowmanager.cpp:588)
==18380==    by 0x58D7F9B: QApplicationPrivate::notify_helper(QObject*, QEvent*) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Widgets.so.5.0.0)
==18380==    by 0x58DB364: QApplication::notify(QObject*, QEvent*) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Widgets.so.5.0.0)
==18380==    by 0x6756B9D: QCoreApplication::notifyInternal(QObject*, QEvent*) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Core.so.5.0.0)
==18380==    by 0x6758855: QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Core.so.5.0.0)
==18380==    by 0x679E7C2: postEventSourceDispatch(_GSource*, int (*)(void*), void*) (in /home/tsdgeos/qt5/qtbase/lib/libQt5Core.so.5.0.0)
==18380==    by 0x85B7AB4: g_main_context_dispatch (gmain.c:2715)
==18380==    by 0x85B7DE7: g_main_context_iterate.isra.24 (gmain.c:3290)
==18380==  Address 0x1642bd48 is 88 bytes inside a block of size 128 free'd
==18380==    at 0x4C2A44B: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18380==    by 0x4F0728B: QQuickBehavior::write(QVariant const&) (qquickbehavior.cpp:210)
==18380==    by 0x53EB0FE: QQmlVMEMetaObject::metaCall(QMetaObject::Call, int, void**) (in /home/tsdgeos/qt5/qtdeclarative/lib/libQt5Qml.so.5.0.0)
==18380==    by 0x54FEA08: StoreProperty(QV8Engine*, QObject*, QQmlPropertyData*, v8::Handle<v8::Value>) (in /home/tsdgeos/qt5/qtdeclarative/lib/libQt5Qml.so.5.0.0)
==18380==    by 0x79ED2CE: v8::internal::JSObject::SetPropertyWithCallback(v8::internal::Object*, v8::internal::String*, v8::internal::Object*, v8::internal::JSObject*, v8::internal::StrictModeFlag) (in /home/tsdgeos/qt5/qtjsbackend/lib/libQt5V8.so.5.0.0)
==18380==    by 0x7A0AE71: v8::internal::JSObject::SetPropertyForResult(v8::internal::LookupResult*, v8::internal::String*, v8::internal::Object*, PropertyAttributes, v8::internal::StrictModeFlag) (in /home/tsdgeos/qt5/qtjsbackend/lib/libQt5V8.so.5.0.0)
==18380==    by 0x7A0B2D8: v8::internal::JSReceiver::SetProperty(v8::internal::String*, v8::internal::Object*, PropertyAttributes, v8::internal::StrictModeFlag, bool) (in /home/tsdgeos/qt5/qtjsbackend/lib/libQt5V8.so.5.0.0)
==18380==    by 0x79A8861: v8::internal::StoreIC::Store(v8::internal::InlineCacheState, v8::internal::StrictModeFlag, v8::internal::Handle<v8::internal::Object>, v8::internal::Handle<v8::internal::String>, v8::internal::Handle<v8::internal::Object>) (in /home/tsdgeos/qt5/qtjsbackend/lib/libQt5V8.so.5.0.0)
==18380==    by 0x79A8DF0: v8::internal::StoreIC_Miss(v8::internal::Arguments, v8::internal::Isolate*) (in /home/tsdgeos/qt5/qtjsbackend/lib/libQt5V8.so.5.0.0)
==18380==    by 0x24E8BD20618D: ???
==18380==    by 0x24E8BD237AC9: ???
==18380==    by 0x24E8BD2249E6: ???

Change-Id: Idcb195206d344bb526ee37f9172a6b3c029540db
Reviewed-by: Michael Brasser <michael.brasser@live.com>