Part: GeometryExtensions

========================

fixes #4087

Missing "break" in loop after finding the extension was causing segfault because of null pointer access, as the unique pointer had been std:move-d when found and was thus no longer valid.

src/Mod/Part/App/Geometry.cpp

@@ -316,6 +316,7 @@ void Geometry::setExtension(std::unique_ptr<GeometryExtension> && geo)
             ext->getName() == geo->getName()){
             ext = std::move(geo);
             hasext = true;
+            break;
         }
     }