init: delete code that sets ro.recovery_id

It looks like this code is dead currently.  From history, this was
meant to be used as a way to check that the recovery image is what was
expected during runtime, but that effort never completed, and we have
full verification of the recovery image when booting into recovery
anyway.

The code is functionally dead as is too, since /recovery doesn't
actually exist in any fstab, since recovery is either mounted as a
ramdisk during recovery or not mounted during normal boot.

Test: boot
Change-Id: I48cd324ef0d5a163db2df2648f6042174b83f10e