pseudo: Handle too many files deadlock

pseudo: Handle too many files deadlock

If we have large amounts of parallelism, pseudo can end up with too
many open connections and will no longer accept further connections,
hanging. This patch works around that by closing some clients, allowing
turnover of connections and unblocking the system. The downside is a small
but theoretical window of data loss. This is likely better than locking
up entirely though. Discussions with Peter are onging about how we could
better fix this.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>