We now use phpversion() instead of php_logo_guid()

Before this patch with a .htaccess file on a higher level in the
hierarchy with "Satisfy Any" it has been possible that the directory
protection didn't work as expected.

this is mainly for use with plugin:upgrade and thus will be
cherrypicked into the current stable branch as well.

should we replace the previous javascript based check in the admin
interface with this one as well?

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darcs-hash:20091115153159-f7d6d-d58f94b8a5edfde525186009af144e2bf2c7768b.gz