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

logical/plugin/backend_client.go

@@ -5,9 +5,9 @@ import (
 	"errors"
 	"net/rpc"
 
+	log "github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-plugin"
 	"github.com/hashicorp/vault/logical"
-	log "github.com/mgutz/logxi/v1"
 )
 
 var (
@@ -204,16 +204,6 @@ func (b *backendPluginClient) Setup(ctx context.Context, config *logical.Backend
 		impl: storageImpl,
 	})
 
-	// Shim log.Logger
-	loggerImpl := config.Logger
-	if b.metadataMode {
-		loggerImpl = log.NullLog
-	}
-	loggerID := b.broker.NextId()
-	go b.broker.AcceptAndServe(loggerID, &LoggerServer{
-		logger: loggerImpl,
-	})
-
 	// Shim logical.SystemView
 	sysViewImpl := config.System
 	if b.metadataMode {
@@ -226,7 +216,6 @@ func (b *backendPluginClient) Setup(ctx context.Context, config *logical.Backend
 
 	args := &SetupArgs{
 		StorageID:   storageID,
-		LoggerID:    loggerID,
 		SysViewID:   sysViewID,
 		Config:      config.Config,
 		BackendUUID: config.BackendUUID,