cid#1596833 Uninitialized pointer field

Change-Id: I1f05ef494e7e28bd105b7658072c33b2d274a803
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/167159
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Tested-by: Jenkins

svgio/source/svgreader/svgstyleattributes.cxx

@@ -1300,7 +1300,8 @@ namespace svgio::svgreader
             maDominantBaseline(DominantBaseline::Auto),
             maResolvingParent(33, 0),
             mbStrokeDasharraySet(false),
-            mbContextStroke(false)
+            mbContextStroke(false),
+            maContextStroke(nullptr)
         {
         }