ice: better handling for connection errors

First, on_connect_complete dropped the connection errors but it
must be handled for restarting failed check if necessary.
Then, a problematic case was detected when the controlling agent
got only a few active checks to do, but a passive will succeed.
In the previous version the controlling was failing as soon as
all active checks were checked. Now, if all active are failing
the controlling agent will let some time for passive agents and
then will decide to set the negotiation as failed.

Change-Id: Ica728f55083a34496b031c859ed73b576e1eef26
GitLab: #411