Fix issue referenced in #484 - literal 'server_type' is strcpy'd instead of the variable

THANKS.in

@@ -412,4 +412,5 @@ William Leibzon
 William Pietri
 Wolfgang Rosenauer
 Yannick Charton
+Yusuke Hayashi (yusukeh0710)
 Ziya Suzen

plugins/check_http.c

@@ -1589,7 +1589,7 @@ redir (char *pos, char *status_line)
             if(use_ssl)
                 strcpy (type,"https");
             else
-                strcpy (type,"server_type");
+                strcpy (type,server_type);
             xasprintf(&url, "/%s", url);
             use_ssl = server_type_check (type);
             i = server_port_check (use_ssl);