OS-1971 fix case where data comes in while we're cleaning up zoneevent watcher and VM.js throws uncaught exception.
OS-1964 Fix log flushing in vmadm
OS-1974 / OS-1834 fix problems with many snapshots and serialize zfs list commands.

OS-1974 don't lose data when there are many snapshots
OS-1834 don't run multiple 'zfs list' commands at the same time
OS-1980: vmadm update: setting firewall_enabled doesn't enable / disable ipf
joyent/smartos-live#180 drop faulty logic sanity checks for image name from zfs origin
OS-1962 / OS-1791 stopping a non-running VM should be a noop.
OS-1874 vmadmd should ignore zone transitions that it doesn't care about.
OS-1866 validate should reject payloads that contain invalid image_uuids
OS-1995 VM tests should use imgadm to ensure images are installed
OS-2000 SATA hotplug should have nice things
Reviewed by: Keith Wesolowski <keith.wesolowski@joyent.com>
OS-1978 don't spew error about zone not existing when we're confirming it was deleted.
OS-1865 keep output from zonecfg/zoneadm commands so we can track failures coming from brand scripts.
OS-1981: enabling / disabling the firewall for a VM ignores remote VMs
OS-1773 update last_modified timestamp for a VM after create-snapshot or delete-snapshot
OS-2011 make vmadm more helpful when you pass in invalid JSON.
IMGAPI-111 imgadm v2 blows up with "TypeError: Cannot read property 'size' of undefined" on import

Fix a few problems here: handle error in getting file info preparing
for streaming down an image; improve error message handling in imgapi
client.getImageFileStream; only attempt to import *active* images.
IMGAPI-114 imgadm v2 SourcePing error message doesn't give any details
IMGAPI-113 imgadm v2 allows you to specify the same source twice with and without a '/'

Also, limit response body output for a source ping error (IMGAPI-114).
IMGAPI-114 imgadm v2 SourcePing error message doesn't give any details

update to latest imgadm deps
IMGAPI-112 imgadm v2 considers import of already existing image an error