software/slaprunner: drop useless X-Accel-Mapping headers

We are not using this

software/slaprunner/buildout.hash.cfg

@@ -38,7 +38,7 @@ md5sum = bd0ad0b80d2b39189f9665c48f1b3830
 
 [template_nginx_conf]
 filename = nginx_conf.in
-md5sum = 862aa0e482927e023e63631087f92190
+md5sum = a042e52e0594ec0486cff7dc896cb6ce
 
 [template_httpd_conf]
 filename = httpd_conf.in

software/slaprunner/nginx_conf.in

@@ -42,7 +42,6 @@ http {
             proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
             proxy_set_header   X-Forwarded-Host  $http_host;
             proxy_set_header   Host              $http_host;
-            proxy_set_header   X-Accel-Mapping   /private/;
             proxy_connect_timeout 200;
             proxy_send_timeout    200;
             proxy_read_timeout    200;
@@ -56,7 +55,6 @@ http {
             proxy_set_header   X-Forwarded-For   $proxy_add_x_forwarded_for;
             proxy_set_header   X-Forwarded-Host  $http_host;
             proxy_set_header   Host              $http_host;
-            proxy_set_header   X-Accel-Mapping   /private/;
 
             proxy_pass http://unix:{{ socket }};
         }