fix 2015-survey redirect

htaccess-apache

@@ -30,7 +30,7 @@ RewriteRule ^(.*[^/])$ /$1.html [L]
 RewriteCond %{REQUEST_FILENAME} !-d
 RewriteRule ^(.*)/$  /$1 [R=301,L]
 
-Redirect 302 /2015-survey/ https://docs.google.com/forms/d/1j0LiFdZLjvfwoEyg5FML6z3sFKqV3Ar1mWReonYhatA/viewform
+Redirect 302 /2015-survey https://docs.google.com/forms/d/1j0LiFdZLjvfwoEyg5FML6z3sFKqV3Ar1mWReonYhatA/viewform
 Redirect 302 /contact /authors
 Redirect 302 /contribute /community
 Redirect 302 /download /install