Move to "github.com/hashicorp/go-hclog" (#4227)

* logbridge with hclog and identical output

* Initial search & replace

This compiles, but there is a fair amount of TODO
and commented out code, especially around the
plugin logclient/logserver code.

* strip logbridge

* fix majority of tests

* update logxi aliases

* WIP fixing tests

* more test fixes

* Update test to hclog

* Fix format

* Rename hclog -> log

* WIP making hclog and logxi love each other

* update logger_test.go

* clean up merged comments

* Replace RawLogger interface with a Logger

* Add some logger names

* Replace Trace with Debug

* update builtin logical logging patterns

* Fix build errors

* More log updates

* update log approach in command and builtin

* More log updates

* update helper, http, and logical directories

* Update loggers

* Log updates

* Update logging

* Update logging

* Update logging

* Update logging

* update logging in physical

* prefixing and lowercase

* Update logging

* Move phyisical logging name to server command

* Fix som tests

* address jims feedback so far

* incorporate brians feedback so far

* strip comments

* move vault.go to logging package

* update Debug to Trace

* Update go-plugin deps

* Update logging based on review comments

* Updates from review

* Unvendor logxi

* Remove null_logger.go

command/approle_concurrency_integ_test.go

@@ -4,12 +4,12 @@ import (
 	"sync"
 	"testing"
 
+	log "github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/vault/api"
 	credAppRole "github.com/hashicorp/vault/builtin/credential/approle"
 	vaulthttp "github.com/hashicorp/vault/http"
 	"github.com/hashicorp/vault/logical"
 	"github.com/hashicorp/vault/vault"
-	logxi "github.com/mgutz/logxi/v1"
 )
 
 func TestAppRole_Integ_ConcurrentLogins(t *testing.T) {
@@ -17,7 +17,7 @@ func TestAppRole_Integ_ConcurrentLogins(t *testing.T) {
 	coreConfig := &vault.CoreConfig{
 		DisableMlock: true,
 		DisableCache: true,
-		Logger:       logxi.NullLog,
+		Logger:       log.NewNullLogger(),
 		CredentialBackends: map[string]logical.Factory{
 			"approle": credAppRole.Factory,
 		},