fix typo in the man page

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

man/man5/nfs4_acl.5

@@ -202,7 +202,7 @@ if either this
 .I permission 
 is set in the file/directory or if the delete-child 
 .I permission
-is set in its parent direcory.
+is set in its parent directory.
 .TP
 .B D
 delete-child - remove a file or subdirectory from within the given directory