Fix some compiler warnings.

Mostly about deprecated ASCII casts.

Change-Id: I70428913799c15f20a1a5f80be57848e1072e058
Reviewed-on: http://codereview.qt.nokia.com/4158
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>

src/plugins/gstreamer/qgstcodecsinfo.cpp

@@ -93,7 +93,8 @@ QGstCodecsInfo::QGstCodecsInfo(QGstCodecsInfo::ElementType elementType)
 
         gst_caps_remove_structure(caps, 0);
     }
-
+#else
+    Q_UNUSED(elementType);
 #endif // GST_CHECK_VERSION(0,10,31)
 }