Item12896:  Make PHP flags conditional

Otherwise apache has issues if php is not installed.

git-svn-id: http://svn.foswiki.org/trunk@17725 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
Item12839: only create a new default for =authenticate= ... keep =http_allow= and =validate= as before


git-svn-id: http://svn.foswiki.org/trunk@17726 0b4bb1d4-4e5a-0410-9cc4-b2b747904278