Fix widgets with negative values being green

The number used to calculate whether a widget is red or green should be
the same value as the one that is displayed. It was instead calling
a (buggy) method which calculated a different balance to the one
displayed. This patch fixes it to determine the colour using the same
value as the one it is displaying.

Author: czan

app/src/main/java/org/gnucash/android/ui/homescreen/WidgetConfigurationActivity.java

@@ -233,7 +233,7 @@ public static void updateWidget(final Context context, int appWidgetId, String a
 
 		views.setTextViewText(R.id.transactions_summary,
 				accountBalance.formattedString(Locale.getDefault()));
-		int color = account.getBalance().isNegative() ? R.color.debit_red : R.color.credit_green;
+		int color = accountBalance.isNegative() ? R.color.debit_red : R.color.credit_green;
 		views.setTextColor(R.id.transactions_summary, context.getResources().getColor(color));