Ensure va_end() is always called in TextWindow::Printf().

src/textwin.cpp

@@ -294,11 +294,11 @@ void TextWindow::ClearScreen() {
 void TextWindow::Printf(bool halfLine, const char *fmt, ...) {
     if(!canvas) return;
 
+    if(rows >= MAX_ROWS) return;
+
     va_list vl;
     va_start(vl, fmt);
 
-    if(rows >= MAX_ROWS) return;
-
     int r, c;
     r = rows;
     top[r] = (r == 0) ? 0 : (top[r-1] + (halfLine ? 3 : 2));