examples/deployment: define default for $NAMESPACE
examples/deployment: define default for $NAMESPACE

Commit 8a50790 requires the definition of a default namespace for
deploy.sh to succeed. This was added to the ci-config but not to
the example one.

google/trillian,RJPercival/trillian,gdbelvin/trillian,gdbelvin/trillian,gdbelvin/trillian,AlCutter/trillian,RJPercival/trillian,google/trillian,AlCutter/trillian