directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/command/mount_notsupported.go

@@ -0,0 +1,15 @@
+// +build !linux
+// +build !darwin
+
+package command
+
+import (
+	"fmt"
+	"runtime"
+)
+
+func runMount(cmd *Command, args []string) bool {
+	fmt.Printf("Mount is not supported on %s %s\n", runtime.GOOS, runtime.GOARCH)
+
+	return true
+}