Fix the issue of segmentation fault when the pattern of a mbe is not setted. For Skia graphic engine, a mbe does not always have a pattern. For example, a color paint does not set a pattern on a mbe for a shape. So, we check if pattern is setted before accessing it.

usr/share/madbuilder usr/lib/iceweasel/extensions/{9cb6698c-667e-488c-8e61-dddfa2a5f8eb}