Enable cron job on NFS server to remove old snippet uploads

Production Change - Criticality 3 C3

Change Objective	Enable a clean-up cron job on share-01
Change Type	C3
Services Impacted	Snippet caching
Change Team Members	@cmcfarland
Change Severity	~S3
Buddy check or tested in staging	The change was tested on staging share-01
Schedule of the change	05/20/2019 10:15am EDT
Duration of the change	10 minutes
Detailed steps for the change. Each step must include:	See Below

The cron job is already in chef, but it depends on the node attribute to be enabled. Basically, the plan is to add this option into the normal chef node attributes:

"gitlab-server": {
      "clean-snippets": {
        "enable": true
      }
    },

There is no real rollback plan since the cron may delete temporary files that it should not. If there is a problem, we can set the "enable" attribute to false and run chef on share-01 to make sure the cron is removed.