Fix problems with veridex packaging

Using global variables means that some other makefile could have changed
these values between the time they were set here and when they were
evaluated. Use target-specific variables to fix this.

Use `soong_zip` instead of `zip` to get reproducible outputs.

hide is no longer necessary

Test: m out/host/linux-x86/obj/PACKAGING/veridex_intermediates/veridex.zip
Change-Id: I66527c92dcaeb229add892eb0b1e30773b780131