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_supported.go

@@ -0,0 +1,19 @@
+// +build !windows,!openbsd,!netbsd,!plan9,!solaris
+
+package stats
+
+import (
+	"syscall"
+)
+
+func (disk *DiskStatus) fillInStatus() {
+	fs := syscall.Statfs_t{}
+	err := syscall.Statfs(disk.Dir, &fs)
+	if err != nil {
+		return
+	}
+	disk.All = fs.Blocks * uint64(fs.Bsize)
+	disk.Free = fs.Bfree * uint64(fs.Bsize)
+	disk.Used = disk.All - disk.Free
+	return
+}