Move busybox binary-dep to ramdisk element

Busybox should be installed and managed from the ramdisk element,
since that is common to all elements that need busybox.  In
addition, we do not want busybox installed when building Dracut
ramdisks, so it can't be in the deploy-* elements.

Change-Id: I2656d20b466138f7f6dfcf558ba90c6909151d3c
Merge "Move busybox binary-dep to ramdisk element"