Switch file context of odm(/.*) to vendor_file

/odm partition is the extension of /vendor partition, so we should not
use system_file for it. Currently there is no ABI between vendor and
odm. We can use 'odm_file' when needed in the future.

Bug: 64240127
Test: boot a device
Change-Id: I4e8300d597aeeba60a255c8d114a54b24bc39470