libcurl: security bump to version 7.39.0

Fixes:
CVE-2014-3707 - libcurl's function curl_easy_duphandle() has a bug that
can lead to libcurl eventually sending off sensitive data that was not
intended for sending.

Removed patch that was upstream and now in the release.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Tested-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>