Do not try to remove the enclosing directory of sockets.

* agent/gpg-agent.c (remove_socket): Do not remove the enclosing
directory.
* scd/scdaemon.c (cleanup): Ditto.

The socket directory is now below /run or at ~/.gnupg. Thus we should
not try to remove the directory of the socket. The auto-removal was
introduced at a time we used a temporary directory for the sockets.

• Signed-off-by: Werner Koch <wk@gnupg.org>