Ignore IfModule block if Module is not loaded

[Poil]

On Debian/Ubuntu you have blocks for each MPM, when apache-buddy extract the value it take the last value, here the MaxClients from the event MPM, but I'm in prefork

<IfModule mpm_prefork_module>
    StartServers         4
    MinSpareServers      5
    MaxSpareServers      20
    MaxClients           30
    MaxRequestsPerChild  4000
</IfModule>

<IfModule mpm_event_module>
    StartServers          2
    MaxClients          150
    MinSpareThreads      25
    MaxSpareThreads      75
    ThreadLimit          64
    ThreadsPerChild      25
    MaxRequestsPerChild   0
</IfModule>

# apache2 -l
Compiled in modules:
  core.c
  mod_log_config.c
  mod_logio.c
  mod_version.c
  prefork.c
  http_core.c
  mod_so.c