The Client.allocs map now contains all AllocRunners again, not just
un-GC'd AllocRunners. Client.allocs is only pruned when the server GCs
allocs.
Also stops logging "marked for GC" twice.
* alloc_runner
* Random tests
* parallel task_runner and no exec compatible check
* Parallel client
* Fail fast and use random ports
* Fix docker port mapping
* Make concurrent pull less timing dependant
* up parallel
* Fixes
* don't build chroots in parallel on travis
* Reduce parallelism on travis with lxc/rkt
* make java test app not run forever
* drop parallelism a little
* use docker ports that are out of the os's ephemeral port range
* Limit even more on travis
* rkt deadline
