Replace ca.pem by up-to-date cert

This is the current cloudapi pem file with the non-outdated digicert CA.

The current one:

```
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1116160165 (0x428740a5)
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=Entrust.net, OU=www.entrust.net/CPS incorp. by ref. (limits liab.), OU=(c) 1999 Entrust.net Limited, CN=Entrust.net Secure Server Certification Authority
        Validity
            Not Before: Oct  1 05:00:00 2006 GMT
            Not After : Jul 26 18:15:15 2014 GMT
        Subject: C=US, O=DigiCert Inc, OU=www.digicert.com, CN=DigiCert High Assurance EV Root CA
```