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.go

@@ -7,9 +7,8 @@ import (
 
 	"google.golang.org/grpc"
 
-	hclog "github.com/hashicorp/go-hclog"
+	log "github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-plugin"
-	"github.com/hashicorp/vault/helper/logbridge"
 	"github.com/hashicorp/vault/logical"
 	"github.com/hashicorp/vault/logical/plugin/pb"
 )
@@ -18,12 +17,18 @@ import (
 type BackendPlugin struct {
 	Factory      logical.Factory
 	metadataMode bool
-	Logger       hclog.Logger
+	Logger       log.Logger
 }
 
 // Server gets called when on plugin.Serve()
 func (b *BackendPlugin) Server(broker *plugin.MuxBroker) (interface{}, error) {
-	return &backendPluginServer{factory: b.Factory, broker: broker}, nil
+	return &backendPluginServer{
+		factory: b.Factory,
+		broker:  broker,
+		// We pass the logger down into the backend so go-plugin will forward
+		// logs for us.
+		logger: b.Logger,
+	}, nil
 }
 
 // Client gets called on plugin.NewClient()
@@ -37,7 +42,7 @@ func (b BackendPlugin) GRPCServer(broker *plugin.GRPCBroker, s *grpc.Server) err
 		factory: b.Factory,
 		// We pass the logger down into the backend so go-plugin will forward
 		// logs for us.
-		logger: logbridge.NewLogger(b.Logger).LogxiLogger(),
+		logger: b.Logger,
 	})
 	return nil
 }