Enable php-fpm Apache conf

Due to a typo in configuration (a dropped backslash), php-fpm's
configuration file was not being enabled. Fix the line in the backend
provisioner script.

Co-authored-by: Liam Lloyd <liam@permanent.org>

Author: meisekimiu

provisioners/configure.sh

@@ -121,8 +121,8 @@ a2enmod \
   mpm_event \
   proxy \
   proxy_fcgi \
-  rewrite
-  setenvif \
+  rewrite \
+  setenvif
 a2enconf \
   charset \
   global-server-name \