We cannot use list_entry() on an empty list. Without history
we have to return an empty line. This fixes a crash when the
cursor up button is pressed and no command has been entered
previously. Broken since:
commit ada160a
Author: Sascha Hauer <s.hauer@pengutronix.de>
Date: Tue Jul 29 11:54:26 2014 +0200
readline: reimplement history functions
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reported-by: Teresa Gamez <t.gamez@phytec.de>