Merge branch 'sz/maint-curl-multi-timeout'

Sometimes curl_multi_timeout() function suggested a wrong timeout
value when there is no file descriptors to wait on and the http
transport ended up sleeping for minutes in select(2) system call.
Detect this and reduce the wait timeout in such a case.

* sz/maint-curl-multi-timeout:
  Fix potential hang in https handshake

diff --cc http.c
Simple merge