Replace `pkey_eq` with `EVP_PKEY_cmp`

In tortls.c the comment says:

/* We'd like to do this, but openssl 0.9.7 doesn't have it:
    return EVP_PKEY_cmp(a,b) == 1; 
*/

Which is true, but AFAIK tor now depends on openssl 0.9.8 which seem to have this function:

openssl-0.9.8$ grep EVP_PKEY_cmp * -R
crypto/evp/evp.h:int EVP_PKEY_cmp(const EVP_PKEY *a, const EVP_PKEY *b);

Trac:
Username: marek