Clarify the _doing_it_wrong message for conditioanl tags. init prevents the...

Clarify the _doing_it_wrong message for conditioanl tags. init prevents the fatal error, but the query still isn't run. Just drop the mention of a hook and we end up with better reasoning why this doesn't work to boot. see #14729.

git-svn-id: https://core.svn.wordpress.org/trunk@17083 1a063a9b-81f0-0310-95a4-ce76da25c4cd