cifs: add fallback in is_path_accessible for old servers

cifs: add fallback in is_path_accessible for old servers

BugLink: http://bugs.launchpad.net/bugs/788691

commit 221d1d797202984cb874e3ed9f1388593d34ee22 upstream.

The is_path_accessible check uses a QPathInfo call, which isn't
supported by ancient win9x era servers. Fall back to an older
SMBQueryInfo call if it fails with the magic error codes.

Reported-and-Tested-by: Sandro Bonazzola <sandro.bonazzola@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Steve Conklin <sconklin@canonical.com>