Stats Reporter causes a NPE. StatsReporter is new and nil in all repos.

[n3wscott]

This causes a NPE. StatsReporter is new and nil in all repos.

Originally posted by @n3wscott in https://github.com/knative/pkg/pull/503/files#diff-1034b06755820a5860e30a206b72a333R459

[n3wscott]

/assign @anniefu