Make annotations defaults consistent

[migmartri]

Based on this discussion https://github.com/kubeapps/kubeapps/pull/587/files#r215954708

See below the comparative based on the template render before and after the change with ingress enabled:

helm template . --set ingress.enabled=true > /tmp/[before/after]_change.yaml

The change does not affect the default outputs, the mongoDB password is expected to be generated

diff /tmp/before_change.yaml /tmp/after_change.yaml 
14c14
<   mongodb-root-password: "TTI2Qlc0dXY2Sg=="
---
>   mongodb-root-password: "NVplRXVTVVRvcQ=="

[prydonius]

lgtm

[arapulido]

Thanks!