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