Based on the same reason behind DEBIAN's switch from ftp:
https://www.debian.org/News/2017/
20170425
(From OE-Core rev:
ba119d836c0f4b20a39c92fa2e64abb0d5a55ad4)
Signed-off-by: Maxin B. John <maxin.john@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
${DEBIAN_MIRROR} http://ftp.es.debian.org/debian/pool \n \
${DEBIAN_MIRROR} http://ftp.se.debian.org/debian/pool \n \
${DEBIAN_MIRROR} http://ftp.tr.debian.org/debian/pool \n \
-${GNU_MIRROR} ftp://mirrors.kernel.org/gnu \n \
+${GNU_MIRROR} https://mirrors.kernel.org/gnu \n \
${KERNELORG_MIRROR} http://www.kernel.org/pub \n \
${GNUPG_MIRROR} ftp://ftp.gnupg.org/gcrypt \n \
${GNUPG_MIRROR} ftp://ftp.franken.de/pub/crypt/mirror/ftp.gnupg.org/gcrypt \n \