minor #1398 Update nginx sample with PHP7 as default (SpacePossum)

This PR was submitted for the master branch but it was merged into the 1.3 branch instead (closes #1398).

Discussion
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Update nginx sample with PHP7 as default

welcome PHP7 :)

Commits
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e8376e54 Update nginx sample with PHP7 as default

doc/web_servers.rst

@@ -57,7 +57,7 @@ The **minimum configuration** to get your application running under Nginx is:
         # location ~ ^/(index|index_dev)\.php(/|$) {
         location ~ ^/index\.php(/|$) {
             # the ubuntu default
-            fastcgi_pass   unix:/var/run/php5-fpm.sock;
+            fastcgi_pass   unix:/var/run/php/phpX.X-fpm.sock;
             # for running on centos
             #fastcgi_pass   unix:/var/run/php-fpm/www.sock;