Verify exact match for volume metadata update.

Test_update_volume_metadata completely replaces a volume's existing
metadata with a new set, discarding any existing values.  Change the
assertion check to an exact match, not merely contains(), to ensure
that no stale metadata is present after update_all.

Change-Id: I1d363cfa65cb7c76fae9cfabaa499dcdf7c8b0ca
Closes-Bug: 1459351
1 file changed