Revert "Fix verify algorithm."

This reverts commit 47daa155

.

The above commit was backported to the 1.0.2 branch as part of backporting
the alternative chain verify algorithm changes. However it has been pointed
out (credit to Shigeki Ohtsu) that this is unnecessary in 1.0.2 as this
commit is a work around for loop checking that only exists in master.

Reviewed-by: Richard Levitte <levitte@openssl.org>