extraManifests type mismatch

[marcuz]

Not setting any values for extraManifests broke chart installation process, because the type was invalid.

Before change:

$ helm lint charts/zipkin/
==> Linting charts/zipkin/
[INFO] Chart.yaml: icon is recommended
[ERROR] values.yaml: - extraManifests: Invalid type. Expected: object, given: array

[ERROR] templates/: values don't meet the specifications of the schema(s) in the following chart(s):
zipkin:
- extraManifests: Invalid type. Expected: object, given: array

After change:

$ helm lint charts/zipkin/
==> Linting charts/zipkin/
[INFO] Chart.yaml: icon is recommended

1 chart(s) linted, 0 chart(s) failed

[codefromthecrypt]

sounds like adding helm lint to CI would be a welcome improvement

ps I think your master is a bit behind, hence the test fail. I'll merge anyway