Renames CT_POLICY_EVAL_CTX.pod to CT_POLICY_EVAL_CTX_new.pod

util/fix-doc-nits.pl complains that
"CT_POLICY_EVAL_CTX (filename) missing from NAME section".
Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>