Add page_cycler test machine setup notes to httpd2_linux.conf. No Code Change.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/256069

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28071 0039d316-1c4b-4281-b951-d872f2087c98