(GH-81) Enable client ssl cert for metrics

Prior to this commit, all trapperkeeper metrics were not using the
client ssl certificate. With the changes in PE-28647 to enable
authentication in metrics collection, we now need to leverage the
`auth.conf` rules which require client ssl authentication. This commit
defaults to using the client ssl for all tk metrics.

Author: Jarret Lavallee

files/tk_metrics

@@ -1,7 +1,6 @@
 #!/opt/puppetlabs/puppet/bin/ruby
 
-# Metrics endpoints for our Trapper Keeper services do not require a client certificate.
-USE_CLIENTCERT = false
+USE_CLIENTCERT = true
 
 require_relative 'pe_metrics'