When using qt in a different language than english, it shows the copyright string twice:

ar:
![screenshot from 2016-06-29 22-38-39](https://cloud.githubusercontent.com/assets/6399679/16468027/4f8b3f16-3e4a-11e6-8196-ab4f64dc3a69.png)

en:
![screenshot from 2016-06-29 22-38-30](https://cloud.githubusercontent.com/assets/6399679/16468028/4f918042-3e4a-11e6-994e-7ad8f6235acc.png)

{
#ifdef WIN32
    
    WSADATA wsadata;
    int ret = WSAStartup(MAKEWORD(2,2), &wsadata);
    if (ret != NO_ERROR || LOBYTE(wsadata.wVersion ) != 2 || HIBYTE(wsadata.wVersion) != 2)
        return false;
#endif
    return true;
}
int GetNumCores()
{
#if BOOST_VERSION >= 105600
    return boost::thread::physical_concurrency();
#else 
    return boost::thread::hardware_concurrency();
#endif
}
std::string CopyrightHolders(const std::string& strPrefix)
{
    std::string strCopyrightHolders = strPrefix + _(COPYRIGHT_HOLDERS);
    if (strCopyrightHolders.find("%s") != strCopyrightHolders.npos) {
        strCopyrightHolders = strprintf(strCopyrightHolders, _(COPYRIGHT_HOLDERS_SUBSTITUTION));
    }
    if (strCopyrightHolders.find("Bitcoin Core developers") == strCopyrightHolders.npos) {
        strCopyrightHolders += "\n" + strPrefix + "The Bitcoin Core developers";
    }
    return strCopyrightHolders;
}