Revert "Avoid ELOOP on auto-mounted snapshots"

This reverts commit 7afcf5b which
accidentally introduced a regression with the .zfs snapshot directory.
While the updated code still does correctly mount the requested
snapshot.  It updates the vfsmount such that it references the
original dataset vfsmount.  The result is that the snapshot itself
isn't visible.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #816

module/zfs/zpl_ctldir.c

@@ -356,13 +356,6 @@ zpl_snapdir_automount(struct path *path)
 	if (error)
 		return ERR_PTR(error);
 
-	/*
-	 * Ensure path->dentry points to the dentry for the root of the
-	 * newly-mounted snapshot, otherwise this function may be called
-	 * repeatedly which can lead to an incorrect ELOOP error return.
-	 */
-	follow_up(path);
-
 	/*
 	 * Rather than returning the new vfsmount for the snapshot we must
 	 * return NULL to indicate a mount collision.  This is done because