Cleanup and fixes (#3273)

* newRequestID() (previously generateUploadID()) returns string than byte array.
* Remove unclear comments and added appropriate comments.
* SHA-256, MD5 Hash functions return Hex/Base64 encoded string than byte array.
* Remove duplicate MD5 hasher functions.
* Rename listObjectsValidateArgs() into validateListObjectsArgs()
* Remove repeated auth check code in all bucket request handlers.
* Remove abbreviated names in bucket-metadata
* Avoid nested if in bucketPolicyMatchStatement()
* Use ioutil.ReadFile() instead of os.Open() and ioutil.ReadAll()
* Set crossDomainXML as constant.

cmd/s3-peer-router.go

@@ -32,7 +32,7 @@ type s3PeerAPIHandlers struct {
 
 func registerS3PeerRPCRouter(mux *router.Router) error {
 	s3PeerHandlers := &s3PeerAPIHandlers{
-		&localBMS{
+		&localBucketMetaState{
 			ObjectAPI: newObjectLayerFn,
 		},
 	}