[BUG] appsession lookup in URL does not work

[BUG] appsession lookup in URL does not work

We've been trying to use the latest release (1.3.14.2) of haproxy  to do
sticky sessions.  Cookie insertion is not an option for us, although we
would much rather use it, as we are trying to work around a problem where
cookies are unreliable.  The appsession functionality only partially worked
(it wouldn't read the session id out of a query string) until we made the
following code change to the get_srv_from_appsession function in
proto_http.c.
(cherry picked from commit 6d0b1fac23517f16b3972b529ea41718b3643c9f)