fix: tests: grep for '$key =' in metadata

fix: tests: grep for '$key =' in metadata

Always grep for '$key =' to avoid a collision with a value, for example
if you are looking for the 'domain' key and your hostname contains
'domain'.

While we are here, add a bunch of logging to facilitate debugging in the
future.

Change-Id: I09197169ab7f842921c9139fdeb36007d7b20cfb
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>