Fix monitor apache configuration template to avoid:

"Scoreboard is full,not at MaxRequestWorkers" errors in monitor instance logs.

See https://httpd.apache.org/docs/2.4/mod/mpm_common.html#serverlimit,
which indicates to set MaxClients rather than ServerLimit.

stack/monitor/buildout.cfg

@@ -61,7 +61,7 @@ eggs =
 # Monitor templates files
 [monitor-httpd-conf]
 <= monitor-template-base
-md5sum = f2d6951670733de3b37c0ebe9eee343b
+md5sum = 74723d46ad34d0b93a00c3b9223fb99b
 filename = monitor-httpd.conf.in
 
 [monitor-template-wrapper]

stack/monitor/templates/monitor-httpd.conf.in

 PidFile "{{ parameter_dict.get('pid-file') }}"
 
 StartServers 1
-ServerLimit 1
+MaxClients 4
 ThreadLimit 4
 ThreadsPerChild 4