Add UTCNow() function. (#3931)

This patch adds UTCNow() function which returns current UTC time.

This is equivalent of UTCNow() == time.Now().UTC()

cmd/lock-rpc-server-common_test.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ * Minio Cloud Storage, (C) 2016, 2017 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,8 +32,8 @@ func TestLockRpcServerRemoveEntryIfExists(t *testing.T) {
 		node:          "host",
 		rpcPath:       "rpc-path",
 		uid:           "0123-4567",
-		timestamp:     time.Now().UTC(),
-		timeLastCheck: time.Now().UTC(),
+		timestamp:     UTCNow(),
+		timeLastCheck: UTCNow(),
 	}
 	nlrip := nameLockRequesterInfoPair{name: "name", lri: lri}
 
@@ -69,16 +69,16 @@ func TestLockRpcServerRemoveEntry(t *testing.T) {
 		node:          "host",
 		rpcPath:       "rpc-path",
 		uid:           "0123-4567",
-		timestamp:     time.Now().UTC(),
-		timeLastCheck: time.Now().UTC(),
+		timestamp:     UTCNow(),
+		timeLastCheck: UTCNow(),
 	}
 	lockRequesterInfo2 := lockRequesterInfo{
 		writer:        true,
 		node:          "host",
 		rpcPath:       "rpc-path",
 		uid:           "89ab-cdef",
-		timestamp:     time.Now().UTC(),
-		timeLastCheck: time.Now().UTC(),
+		timestamp:     UTCNow(),
+		timeLastCheck: UTCNow(),
 	}
 
 	locker.lockMap["name"] = []lockRequesterInfo{
@@ -116,7 +116,7 @@ func TestLockRpcServerRemoveEntry(t *testing.T) {
 
 // Tests function returning long lived locks.
 func TestLockRpcServerGetLongLivedLocks(t *testing.T) {
-	ut := time.Now().UTC()
+	ut := UTCNow()
 	// Collection of test cases for verifying returning valid long lived locks.
 	testCases := []struct {
 		lockMap      map[string][]lockRequesterInfo