Allow hard reboots when still attempting a soft reboot

Commit cc0be157d005c5588fe5db779fc30fefbf22b44d introduced a
regression in the reboot code. Previously, a hard reboot could be
performed when an instance was in soft reboot.

This fixes the regression by allowing a hard reboot when the instance
is in one of the two new task states.

Closes-bug: 1362799
Change-Id: Id8aaf852b0cccb75a79794a8bf9eb94e21550b81
Merge "Allow hard reboots when still attempting a soft reboot"