add max_connections parameter required with big zeo configuration

slapos/recipe/erp5/template/my.cnf.in

@@ -22,6 +22,10 @@ query_cache_size = 32M
 
 plugin-load = ha_innodb_plugin.so
 
+# By default only 100 connections are allowed, when using zeo
+# we may have much more connections
+# max_connections = 1000
+
 # The following are important to configure and depend a lot on to the size of
 # your database and the available resources.
 #innodb_buffer_pool_size = 4G