apache: remove php5-cgi support, always generate php config

apache: remove php5-cgi support, always generate php config

Only fastcgi php is supported going forward since suphp has long been
deprecated.

Config.Apache.defaultPhpVersion has been removed; since PhpVersion
will always be specified, there is no reason for domtool not to
explicitly generate config instead of relying on the ambient apache
config to set default handlers for php.

The kerberos/afs fastcgi wrapper is suppressed on non-waklog systems,
but ONLY when php is configured from PhpVersion in the vhost as a
whole; the phpVersion and fastScriptAlias actions don't have access to
the node they are being generated on, and can't detect that waklog is
not supported. Will need to be fixed eventually...