BUG/MINOR: mux-h1: Properly handle http-request and http-keep-alive timeouts

BUG/MINOR: mux-h1: Properly handle http-request and http-keep-alive timeouts

It is now the turn for the H1 mux to be fix to properly handle http-request
and http-keep-alive timeouts. It is quite surprising but it is broken since
the 2.2. For idle connections on client side, the smallest value between the
client timeout and the http-request/http-keep-alive timeout is used while
the client timeout should only be used if other ones are not defined. So, if
the client timeout is the smallest value, the keep-alive timeout is not
respected.

It is only an issue for idle client connections. The http-request timeout is
respected from the moment part of the next request was received.

This patch should fix the issue #2334. It must be backported as far as 2.2. But
be careful during the backports. The H1 mux had evolved a lot since the 2.2.