ssh tools: Split connect and communication phases
We can fallback after a connect error, but we cannot easily fall back
once we start sending data as we may have consumed part of the buffer so
reconnecting and sending what's left would not make sense.
Therefore we now fallback on connect errors, but we issue a hard fail if
error happens after communication has been established.
Resolves:
https://pagure.io/SSSD/sssd/issue/1498
Merges: https://pagure.io/SSSD/sssd/pull-request/3383
Signed-off-by: Simo Sorce <simo@redhat.com>
Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>