Don't check for /dev/kvm

Previously we were not running any CompOS related code if /dev/kvm was
not present. But this is not the appropriate check - other VMs are
possible.

I could migrate to checking the newly-introduced properties, but
actually odsign has no reason to check VM capabilities:

- Normally CompOS should not be present on a device that is not
  VM-capable.
- Even if it is, it will not generate key files or artifacts, so
  odsign won't do any significant work.
- Even if key files did appear, compos_verify_key would fail cleanly &
  quickly, preventing any further processing.

Test: boot odsign with & without CompOS files
Test: presubmits
Bug: 217687661
Change-Id: I6edee914f63f8ed579f65c07ce0dc3ad851da541
1 file changed