rpc: Remove time check for each RPC calls. (#3804)

This removal comes to avoid some redundant requirements
which are adding more problems on a production setup.

Here are the list of checks for time as they happen

 - Fresh connect (during server startup) - CORRECT
 - A reconnect after network disconnect - CORRECT
 - For each RPC call - INCORRECT.

Verifying time for each RPC aggravates a situation
where a RPC call is rejected in a sequence of events
due to enough load on a production setup. 3 second
might not be enough time window for the call to be
initiated and received by the server.

cmd/s3-peer-rpc-handlers_test.go

@@ -20,7 +20,6 @@ import (
 	"encoding/json"
 	"path"
 	"testing"
-	"time"
 )
 
 type TestRPCS3PeerSuite struct {
@@ -62,7 +61,7 @@ func TestS3PeerRPC(t *testing.T) {
 // Test S3 RPC handlers
 func (s *TestRPCS3PeerSuite) testS3PeerRPC(t *testing.T) {
 	// Validate for invalid token.
-	args := AuthRPCArgs{AuthToken: "garbage", RequestTime: time.Now().UTC()}
+	args := AuthRPCArgs{AuthToken: "garbage"}
 	rclient := newRPCClient(s.testAuthConf.serverAddr, s.testAuthConf.serviceEndpoint, false)
 	defer rclient.Close()
 	err := rclient.Call("S3.SetBucketNotificationPeer", &args, &AuthRPCReply{})