trusted certs not working if multiple certs are in the same file

Saw this on a customer call today. The c_rehash function was only creating one hash for a .pem file that had two certificates. (one being an intermediate cert)

Everything worked once we split the certs out into two files.

This was supposed to have been fixed in c_rehash, and was one of the reason I wanted to use c_rehash instead of the old script.

We will need to investigate whether we are building an old version of c_rehash, or if this isn't properly fixed. I've confirmed it works in the c_rehash shipped with ubuntu, but it looks like it's maybe not in the openssl c_rehash.

cc\ @balameb @dblessing