Remove test for empty devnode slice in get_metadata
Remove test for empty devnode slice in get_metadata

We don't need a special check because the standard flow handles this case.

Signed-off-by: Andy Grover <b7d524d2f5cc5aebadb6b92b08d3ab26911cde33@redhat.com>

stratis-storage/stratisd,trgill/stratisd,mulkieran/stratisd,mulkieran/stratisd,stratis-storage/stratisd,trgill/stratisd,stratis-storage/stratisd