Move all backends into backend directory

backend/local/read_device_other.go

@@ -0,0 +1,13 @@
+// Device reading functions
+
+// +build !darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris
+
+package local
+
+import "os"
+
+// readDevice turns a valid os.FileInfo into a device number,
+// returning devUnset if it fails.
+func readDevice(fi os.FileInfo) uint64 {
+	return devUnset
+}