CA-256884: do not crash on client ECONNRESET
CA-256884: do not crash on client ECONNRESET

This relies on the update of `cohttp` and `conduit`.
A new `~on_err` handler allows custom management of
client connection errors, this can be used to improve
logging and solve a regression that was causing
`message-switch` to crash on sudder restart of connected
daemons.

Signed-off-by: Marcello Seri <34fd14c67154e888f6587d5c0e7eadd13aaf7ca7@citrix.com>

xapi-project/message-switch,xapi-project/message-switch,xapi-project/message-switch