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
issue