ncurses: roll back to version 5.7

ncurses 5.8 and 5.9 segfault with some applications so roll back to
version 5.7

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/ncurses/ncurses.mk

@@ -23,9 +23,8 @@
 # USA
 
 # TARGETS
-NCURSES_VERSION = 5.8
+NCURSES_VERSION = 5.7
 NCURSES_SITE = $(BR2_GNU_MIRROR)/ncurses
-NCURSES_SOURCE = ncurses-$(NCURSES_VERSION).tar.gz
 NCURSES_INSTALL_STAGING = YES
 
 NCURSES_CONF_OPT = \