Zun is currently using a string representation of 'command',
but Docker is returning 'Cmd' in string representation. This
requires a conversion of commands between list and string,
which is complicated and error-prone (it might causes bugs like
https://review.openstack.org/#/c/551795/).
It is better to switch from string to list
Co-Authored-By: Hongbin Lu <hongbin034@gmail.com>
Change-Id: Ie0df504a67cc20907d35e3513fd80d3f6be687fd
Closes-Bug: #1755019