Merge branch 'km/imap-send-libcurl-options'

Now imap-send learned to talk to the server using cURL library, allow the same GIT_CURL_VERBOSE environment variable to control the verbosity of the chattering. * km/imap-send-libcurl-options: imap-send.c: set CURLOPT_USE_SSL to CURLUSESSL_TRY imap-send.c: support GIT_CURL_VERBOSE