busybox: disable bzip2

bzip2 adds about 8kb of size. For tiny builds it's often disabled.
It's not directly used by stock OpenWrt programs.
Kernel images compressed with bzip2 are also not fully supported.

Signed-off-by: Sergey Ponomarev <stokito@gmail.com>
[fix \ indention]
Signed-off-by: Paul Spooren <mail@aparcar.org>

package/base-files/files/lib/upgrade/common.sh

@@ -96,7 +96,6 @@ get_image() { # <source> [ <command> ]
 		local magic="$(dd if="$from" bs=2 count=1 2>/dev/null | hexdump -n 2 -e '1/1 "%02x"')"
 		case "$magic" in
 			1f8b) cmd="zcat";;
-			425a) cmd="bzcat";;
 			*) cmd="cat";;
 		esac
 	fi