Follow-up to f858d94, only reinitialize screen when toggling debug mode

The screen_init() call for each print() & C:o caused serious screen
artefacts in debug mode.  This patch reworks f858d94 to only re-init
screen when toggling debug.

Also, avoid screen_init() completely if started in debug mode.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/helpers.c

@@ -110,13 +110,6 @@ void print(int action, const char *fmt, ...)
 	if (log_is_silent())
 		return;
 
-	/*
-	 * In debug mode we must reinitialize often, user may be
-	 * resizing their terminal to cope with debug output.
-	 */
-	if (log_is_debug())
-		screen_init();
-
 	if (fmt) {
 		va_start(ap, fmt);
 		printv(fmt, ap);