Fix unit tests and code to support schema-enforcement by yangtools.

A recent change in yangtools requires fixing tests and code
that did not honor the schema required by the yang data type.
This patch fixes those errors.  This also addresses an incomplete
UUID that was added in a previous patch to the use-cases.

Change-Id: I783f597de12fe1810e6e67d6345e4467fe7db065
Signed-off-by: Thomas Bachman <tbachman@yahoo.com>