Remove ApacheMaxMaxClients property to set apache::mod::prefork::maxclients
and add ApacheMaxRequestWorkers to set apache::mod::prefork::maxrequestworkers
as the current setting ApacheMaxRequestWorkers sets maxclients and this
is confusing. This was due to maxclients being renamed to maxrequestworkers
in the apache configuration so was legacy naming.
Change-Id: I4e0e1beb733ae1c41d74d488481230026611c6c0
Closes-bug: #1871643