Support more concurrent connections for z-push

My logs were showing lots of: 
[04-Sep-2014 15:52:41] WARNING: [pool www] server reached pm.max_children setting (5), consider raising it

setup/zpush.sh

@@ -65,6 +65,10 @@ rm -f /usr/local/lib/z-push/autodiscover/config.php
 cp conf/zpush/autodiscover_config.php /usr/local/lib/z-push/autodiscover/config.php
 sed -i "s/PRIMARY_HOSTNAME/$PRIMARY_HOSTNAME/" /usr/local/lib/z-push/autodiscover/config.php
 
+# Bump up max_children to support more concurrent connections
+tools/editconf.py /etc/php5/fpm/pool.d/www.conf -c ';' \
+	pm.max_children=8
+
 # Some directories it will use.
 
 mkdir -p /var/log/z-push