Refuse to remove an online node (#2086)
Refuse to remove an online node (#2086)

* fix node DELETE to fail if node is still online

* fix cli node rm to first check for node, and fail if still connected

* revert master host nodes remove validation

* consistency: online

mikkopiu/kontena,kontena/kontena,kontena/kontena,kontena/kontena,mikkopiu/kontena,kontena/kontena,mikkopiu/kontena,mikkopiu/kontena