busybox: do not pack relocations for executables

According to https://github.com/CyanogenMod/android_build/commit/f55c5a52ac3d523cdcfb7cd7ab093d01da8b3caf

Fixes building static busybox

Change-Id: Iecd3eefb0c88f17be0b82a028c5860cd713dc7f1
1 file changed