fail_timeout=0 as recommended by Unicorn

Set's fail_timeout=0 as recommended by
http://unicorn.bogomips.org/Unicorn/Configurator.html#method-i-timeout
when Unicorn is running behind nginx.

lib/support/nginx/gitlab

@@ -28,7 +28,7 @@
 ##
 
 upstream gitlab {
-  server unix:/home/git/gitlab/tmp/sockets/gitlab.socket;
+  server unix:/home/git/gitlab/tmp/sockets/gitlab.socket fail_timeout=0;
 }
 
 ## Normal HTTP host

lib/support/nginx/gitlab-ssl

@@ -34,7 +34,7 @@
 ## See installation.md#using-https for additional HTTPS configuration details.
 
 upstream gitlab {
-  server unix:/home/git/gitlab/tmp/sockets/gitlab.socket;
+  server unix:/home/git/gitlab/tmp/sockets/gitlab.socket fail_timeout=0;
 }
 
 ## Normal HTTP host