Support both v2 and v1 push jobs servers
Support both v2 and v1 push jobs servers

Try making a v2 request, and then fall back to only sending the payload
the v1 server comprehends.

Signed-off-by: Thom May <b591b301ff4610f565a21bb050267ffd893cc83c@may.lt>

chef/knife-push,chef/knife-push