Call for testing: OpenSSH 7.2

[Salvador Fandiño]

>
>   * ssh(1): refuse attempts to set ConnectionAttempts=0, which does
>     not make sense and would cause ssh to print an uninitialised stack
>     variable. bz#2500

When using connection multiplexing, I sometimes set ConnectionAttempts 
to 0 in order to avoid opening a new connection when the remote side 
refuses to create new sessions after the top defined by MaxSessions is 
reached.

Having a way to avoid that fall-back behavior is important when writing 
automation scripts. Otherwise, authentication prompts may appear at any 
time, and scripts would have to cope with it.