Bug 10109

Checking with valgrind I got some invalid reads. The message was like the
following:

==6988== Invalid read of size 4
==6988==    at 0x4B3C7FD: intersect_rect (radeon_state.c:61)
==6988==    by 0x4B3C9DA: radeonRecalcScissorRects (radeon_state.c:108)
==6988==    by 0x4B3CAEC: radeonUpdateScissor (radeon_state.c:131)
==6988==    by 0x4B3CD04: radeonEnable (radeon_state.c:205)
==6988==    by 0x4B4B1C1: r300Enable (r300_state.c:542)
==6988==    by 0x4D13827: _mesa_set_enable (enable.c:956)
==6988==    by 0x4D138A6: _mesa_Enable (enable.c:971)
==6988==    by 0x4769879: glEnable (glapitemp.h:1160)

==6988==    by 0x4613A5F:osgUtil::RenderStage::drawImplementation
(osg::RenderInfo&,osgUtil::RenderLeaf*&) (in /usr/lib/libosgUtil.so)
==6988==    by 0x4607658: osgUtil::RenderBin::draw(osg::RenderInfo&,
osgUtil::RenderLeaf*&) (in /usr/lib/libosgUtil.so)
==6988==    by 0x46133BC: osgUtil::RenderStage::drawInner(osg::RenderInfo&,
osgUtil::RenderLeaf*&, bool&) (in /usr/lib/libosgUtil.so)
==6988==    by 0x4612E6C: osgUtil::RenderStage::draw(osg::RenderInfo&,
osgUtil::RenderLeaf*&) (in /usr/lib/libosgUtil.so) ==6988==  Address
0x4AF585C is 4 bytes inside a block of size 8 free'd
==6988==    at 0x402303F: free (vg_replace_malloc.c:233)
==6988==    by 0x4BAF503: _mesa_free (imports.c:93)
==6988==    by 0x4B2FF84: __driUtilUpdateDrawableInfo (dri_util.c:430)
==6988==    by 0x4B2FD46: DoBindContext (dri_util.c:339)
==6988==    by 0x4B2FF00: driBindContext (dri_util.c:383)
==6988==    by 0x4735921: BindContextWrapper (glxext.c:1620)
==6988==    by 0x4735A53: MakeContextCurrent (glxext.c:1674)
==6988==    by 0x4735D7C: glXMakeCurrent (glxext.c:1796)
==6988==    by 0x47D8BB3: Producer::RenderSurface::makeCurrent(bool) (in
/usr/lib/libProducer.so)
==6988==    by 0x47DEEC6:Producer::Camera::_frame(bool) (in /usr/lib/libProducer.so)
==6988==   by 0x47DF75F: Producer::Camera::frame(bool) (in /usr/lib/libProducer.so)
==6988==    by 0x47E2589: Producer::CameraGroup::_singleThreadedFrame()
(in /usr/lib/libProducer.so)