Setting '-e' flag tells shells to exit with error exit code immediately
after any of commands fails, and causes make(1) to regard recipes as
failed.

Before this, make will still continue to succeed even after the
installation failed, for example, for insufficient permission or
directory does not exist.
Signed-off-by: Zhang Bingwu <xtexchooser@duck.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>