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/stats/disk_notsupported.go

@@ -0,0 +1,7 @@
+// +build windows openbsd netbsd plan9 solaris
+
+package stats
+
+func (disk *DiskStatus) fillInStatus() {
+	return
+}