[Bug]: influxdb setting forces optional variables to be set

[borgstorm]

Affected Chart

icinga2

Which version of the app contains the bug?

0.3.0

Please describe your problem

When attempting to enable an https connection to an influxdb the chart fails due to un-set variables.

Helm values:

    influxdb:
      enabled: true
      host: influx
      port: 443
      database: icinga2
      ssl_enable: true
     [...]

error message:

influxdb secret not set. Set .Values.features.influxdb.tlsSecret

Assigning a value to tlsSecret in turn returns similar errors saying that the following are not set:

.Values.features.influxdb.caSecretKey
.Values.features.influxdb.keySecretKey
.Values.features.influxdb.certSecretKey

These attribute are all optional according to the documentation. I have also tested it on a VM install on RHEL and the influx writer works as expected, with ssl_enable: true and without any of the extra attributes.