Revert "Update JSON representations of Capabilities structs to match …

…internal"

This reverts commit ba186d2. I thought this change
would be non-breaking but I was WRONG

server_structs/director.go

@@ -47,11 +47,11 @@ type (
 
 	// Note that the json are kept in uppercase for backward compatibility
 	Capabilities struct {
-		PublicReads bool `json:"PublicReads"`
-		Reads       bool `json:"Reads"`
-		Writes      bool `json:"Writes"`
-		Listings    bool `json:"Listings"`
-		DirectReads bool `json:"DirectReads"`
+		PublicReads bool `json:"PublicRead"`
+		Reads       bool `json:"Read"`
+		Writes      bool `json:"Write"`
+		Listings    bool `json:"Listing"`
+		DirectReads bool `json:"FallBackRead"`
 	}
 
 	NamespaceAdV2 struct {