local: fix symlink/junction point directory handling under Windows

Before this commit rclone's handling of symlinks and junction points
under Windows was broken.  rclone treated them as files and attempted
to transfer them which gave the error "The handle is invalid".

Ultimately the cause of this was 3e43ff7414 which was a
workaround so files with reparse points (which are a kind of symlink)
would transfer correctly.

The solution implemented is to revert the above commit which will mean
that #614 will break again.  However there is now a work-around (which
will be signaled by rclone) to use the -L flag which wasn't available
when the original commit was made.

Fixes #2336

backend/local/local.go

@@ -642,11 +642,6 @@ func (o *Object) Storable() bool {
 		}
 	}
 	mode := o.mode
-	// On windows a file with os.ModeSymlink represents a file with reparse points
-	if runtime.GOOS == "windows" && (mode&os.ModeSymlink) != 0 {
-		fs.Debugf(o, "Clearing symlink bit to allow a file with reparse points to be copied")
-		mode &^= os.ModeSymlink
-	}
 	if mode&os.ModeSymlink != 0 {
 		if !*skipSymlinks {
 			fs.Logf(o, "Can't follow symlink without -L/--copy-links")