[chart] If 'locked' is not specified the runner crashes

Summary

If you dont include in the yaml

runners:
  locked: false # or true

then the runner will crash:

FATAL: could not parse <nil> as value for flag locked: strconv.ParseBool: parsing "<nil>": invalid syntax

Steps to reproduce

I was installing using this command

helm upgrade runner gitlab/gitlab-runner --install --namespace gitlab -f kube-setup/gitlab-runner.yml --set runnerToken=XXX

this is my values file

image: gitlab/gitlab-runner:alpine-v11.5.1
gitlabUrl: https://x.com
concurrent: 30
logLevel: debug
rbac:
  clusterWideAccess: false
  create: true
runners:
  cache:
    cacheType: s3
    cacheShared: true
    s3ServerAddress: s3.amazonaws.com
    s3BucketName: some-bucket
    s3CacheInsecure: "false"
    s3BucketLocation: "eu-west-1"
    s3CachePath: "cache"
  builds:
    cpuRequests: 500m
    cpuLimit: 2000m
    memoryRequests: 256Mi
    memoryLimit: 4Gi
  services:
    cpuRequests: 100m
    cpuLimit: 2000m
    memoryRequests: 128Mi
    memoryLimit: 4Gi
  privileged: true

Actual behavior

I see that the runner pod crashes with the fatal error above

If i add locked: false runner is ok

ALSO this error was only shown when I added logLevel: debug - Seems that a fatal crash error should not be 'debug' visable only!

Expected behavior

I should see that it works.

I should see the error without setting the log level.