Description of problem:
There are no metrics collections from version 5.9.0.13.
* C&U on in the configuration
* Hawkular is up and running
* In the provider's details page:
     * Endpoints table contains the correct URL, Port and type.
     * Status.MetricAuthentication = valid
     * Status.LastMetricsCollection = Unavailable - 3 Minutes Ago


Version-Release number of selected component (if applicable):
5.9.0.13

How reproducible:

Steps to Reproduce:
1. Add provider with hawkular metrics
2. Set C&U configuration to on
3. wait for hawkular validation
4. wait for metrics collection

Actual results:
Last Metrics Collection = Unavailable - 3 Minutes Ago

Expected results:
Last Metrics Collection = Success - 3 Minutes Ago

Additional info:


    Recreation in the rails console:
        ems = ExtManagementSystem.first
        pod = ems.container_groups.first
        context = ManageIQ::Providers::Kubernetes::ContainerManager::MetricsCapture::HawkularCaptureContext.new(pod, 5.minutes.ago, 0.minutes.ago, 30)
        context.collect_metrics
    
    You will see the following output:
        irb(main):020:0> context.collect_metrics
NoMethodError: undefined method `keys' for nil:NilClass
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:136:in `get_metrics_key'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:212:in `block in insert_metrics'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:209:in `each'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:209:in `insert_metrics'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:244:in `collect_metrics_for_object'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/hawkular_capture_context.rb:90:in `collect_group_metrics'
	from /opt/rh/cfme-gemset/bundler/gems/manageiq-providers-kubernetes-165a34709d2d/app/models/manageiq/providers/kubernetes/container_manager/metrics_capture/capture_context_mixin.rb:29:in `collect_metrics'
	from (irb):20
	from /opt/rh/cfme-gemset/gems/railties-5.0.6/lib/rails/commands/console.rb:65:in `start'
	from /opt/rh/cfme-gemset/gems/railties-5.0.6/lib/rails/commands/console_helper.rb:9:in `start'
	from /opt/rh/cfme-gemset/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:78:in `console'
	from /opt/rh/cfme-gemset/gems/railties-5.0.6/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
	from /opt/rh/cfme-gemset/gems/railties-5.0.6/lib/rails/commands.rb:18:in `<top (required)>'
	from bin/rails:4:in `require'
	from bin/rails:4:in `<main>'
irb(main):021:0>