dialog: upgrade to 1.2-20150528

remove use-pkg-config-for-ncurses-detection.patch, the new version is
using the pkg-config to check ncurses
configuration assumes the cf_have_ncuconfig is unknown for cross-compile,
but ncurses is added into DEPENDS, so change it as yes

Signed-off-by: Roy Li <rongqing.li@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>