tweak FP avoidance in TO_IN_SUBJ

git-svn-id: https://svn.apache.org/repos/asf/spamassassin/trunk@1581904 13f79535-47bb-0310-9956-ffa450edef68
AHBL is closing down. disabling early enough. (Axb-2014-03-28)

git-svn-id: https://svn.apache.org/repos/asf/spamassassin/trunk@1581922 13f79535-47bb-0310-9956-ffa450edef68