busybox: adjust download mirror

* Adjust download locations:
  - use https as busybox.net permanently redirects http to https
  - gentoo mirror has neither 1.25.0 nor 1.25.1 available, so drop it
    in favor of buildroot.net that has 1.25.1

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>

package/utils/busybox/Makefile

@@ -13,8 +13,8 @@ PKG_RELEASE:=2
 PKG_FLAGS:=essential
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
-PKG_SOURCE_URL:=http://www.busybox.net/downloads \
-		http://distfiles.gentoo.org/distfiles/
+PKG_SOURCE_URL:=https://www.busybox.net/downloads \
+		http://sources.buildroot.net
 PKG_MD5SUM:=4f4c5de50b479b11ff636d7d8eb902a2
 
 PKG_BUILD_DEPENDS:=BUSYBOX_USE_LIBRPC:librpc BUSYBOX_CONFIG_PAM:libpam