Windows: Factor out syslog and journald

Signed-off-by: John Howard <jhoward@microsoft.com>

daemon/logdrivers_windows.go

@@ -0,0 +1,7 @@
+package daemon
+
+// Importing packages here only to make sure their init gets called and
+// therefore they register themselves to the logdriver factory.
+import (
+	_ "github.com/docker/docker/daemon/logger/jsonfilelog"
+)

daemon/logger/journald/journald.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package journald
 
 import (

daemon/logger/journald/journald_unsupported.go

@@ -0,0 +1,3 @@
+// +build !linux
+
+package journald

daemon/logger/syslog/syslog.go

@@ -1,3 +1,5 @@
+// +build linux
+
 package syslog
 
 import (

daemon/logger/syslog/syslog_unsupported.go

@@ -0,0 +1,3 @@
+// +build !linux
+
+package syslog