Fix for Curl crash in case there is a network timeout.

Hi All,

While working on our cocos2dx game we noticed that the game would occasionally when there were timeout errors. I finally decided to dig in look for a solution. Found out that curl apparently fails to send a timeout notification. The proper fix (as noted on the Curl site as well is to set the following curl option in code)

@ code = curl_easy_setopt(handle, CURLOPT_NOSIGNAL, 1);
if (code != CURLE_OK) {
return false;
}@

And the best place to do this is in extensions/network/HttpClient.cpp in the following function
configureCURL(CURL *handle)

But since, curl options are static, I suppose this can be done anywhere in the code.

Posting this to validate the solution, and hopefully help someone.