Update cache_domains.json

cache_domains.json

@@ -9,6 +9,11 @@
 			"name": "apple",
 			"description": "CDN for apple updates",
 			"domain_files": ["apple.txt"]
+		},
+		{
+			"name": "delldownloads",
+			"description": "CDN for dell downloads",
+			"domain_files": ["delldownloads.txt"]
 		}
 	]
 }