New set of CA certificates is in cacert.pem, used only on Windows.

These CA certificates were copied from debian ca-certificates, which uses
certificates from Mozilla's trust store.

spi CA certificate has be removed, no server in xmpp.net list uses this
CA certificate.
https://xmpp.net/directory.php

I have removed these CA certificates with 1024-bit RSA public keys,
because Mozilla is planning to remove them in Q1 2014 :

Digital_Signature_Trust_Co._Global_CA_1.crt
Digital_Signature_Trust_Co._Global_CA_3.crt
Entrust.net_Secure_Server_CA.crt
Equifax_Secure_CA.crt
Equifax_Secure_eBusiness_CA_1.crt
Equifax_Secure_Global_eBusiness_CA.crt
GTE_CyberTrust_Global_Root.crt
NetLock_Business_=Class_B=_Root.crt
NetLock_Express_=Class_C=_Root.crt
RSA_Root_Certificate_1.crt
Thawte_Premium_Server_CA.crt
Thawte_Server_CA.crt
ValiCert_Class_1_VA.crt
ValiCert_Class_2_VA.crt
Verisign_Class_1_Public_Primary_Certification_Authority.crt
Verisign_Class_1_Public_Primary_Certification_Authority_-_G2.crt
Verisign_Class_2_Public_Primary_Certification_Authority_-_G2.crt
Verisign_Class_3_Public_Primary_Certification_Authority.crt
Verisign_Class_3_Public_Primary_Certification_Authority_-_G2.crt

See:
https://www.mozilla.org/en-US/about/governance/policies/security-group/certs/policy/
https://wiki.mozilla.org/CA:MD5and1024

I'm also removing TurkTrust CA certificates because of this security
incident:
https://blog.mozilla.org/security/2013/01/03/revoking-trust-in-two-turktrust-certficates/

TURKTRUST_Certificate_Services_Provider_Root_1.crt
TURKTRUST_Certificate_Services_Provider_Root_2007.crt
TURKTRUST_Certificate_Services_Provider_Root_2.crt

other/cacert.pem is used only on Windows. On Unix platforms
use CA certificates installed in /etc/ssl/certs
(python-nbxmpp loads CA certificates from /etc/ssl/certs directory)

Fixes #7629