Merge branch 'ky/imap-send-openssl-1.1.0' into maint

Upcoming OpenSSL 1.1.0 will break compilation b updating a few APIs we use in imap-send, which has been adjusted for the change. * ky/imap-send-openssl-1.1.0: configure: remove checking for HMAC_CTX_cleanup imap-send: avoid deprecated TLSv1_method() imap-send: check NULL return of SSL_CTX_new() imap-send: use HMAC() function provided by OpenSSL