Fix the build for Qt5

Merging #3883 broke the Qt5 build, define the color in the standard
way.

Author: laanwj

src/qt/guiconstants.h

@@ -24,7 +24,7 @@ static const int STATUSBAR_ICONSIZE = 16;
 /* Transaction list -- bare address (without label) */
 #define COLOR_BAREADDRESS QColor(140, 140, 140)
 /* Transaction list -- has conflicting transactions */
-#define COLOR_HASCONFLICTING Qt::white;
+#define COLOR_HASCONFLICTING QColor(255, 255, 255)
 /* Transaction list -- has conflicting transactions - background */
 #define COLOR_HASCONFLICTING_BG QColor(192, 0, 0)