Magento : Unknown cipher in list: TLSv1 [duplicate]

First going to Curl.php in downloader/lib/Mage/HTTP/Client/Curl.php,

Edit file going to line no 377 and try changing:

$this->curlOption(CURLOPT_SSL_CIPHER_LIST, 'TLSv1');

to

$this->curlOption(CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);

Done!