tdf#87309: Use black as default currentColor if no color was...

...expecified in File - Open too.

Change-Id: I616e66a296d7c44e5a8784b3a5f32f14ce7a668d
Note: Chrome and Firefox use back as well so IMHO it makes sense to do it this way.
Reviewed-on: https://gerrit.libreoffice.org/19567Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>

filter/source/svg/gfxtypes.hxx

@@ -162,7 +162,7 @@ struct State
         meTextAnchor(BEFORE),
         meTextDisplayAlign(BEFORE),
         mnTextLineIncrement(0.0),
-        maCurrentColor(1.0),
+        maCurrentColor(0.0),
         mbVisibility(true),
         meFillType(SOLID),
         mnFillOpacity(1.0),