Comment 8 for bug 1302156

I didn't manage to recreate the problem yet… I installed the package 1.5+bzr2227-0ubuntu1, created a node with power_type = 'ipmi' and power_parameters = {"power_driver": "", "power_address": "192.168.220.*", "power_pass": "*", "power_user": "Administrator"}.

Then I ran:
sudo maas-region-admin migrate maasserver 0071_drop_after_commissioning_action
(to rewind the migrations)
sudo maas-region-admin migrate maasserver 0072_remove_ipmi_autodetect
(to run the 0072_remove_ipmi_autodetect migration)

No crash, and I can see the node's power_parameters field being updated (i.e. after the migration has run, node.power_parameters['power_driver'] is 'LAN_2_0').