Fix crash in parse_border()
The bug was introduced in commit:
9b7640b8 by Benjamin Otte, 2012-03-26 17:24:02
styleproperty: Make _gtk_style_property_parse_value() return a CssValue
In that commit, values changed from GValue* to GtkCssValue**,
but one !G_IS_VALUE (&values[8]) was left untouched. As a result,
if border shorthand contains anything after color, it might crash,
depending on memory layout.
Fixes: #751 (closed)
Edited by SyntevoAlex