Comment 5 for bug 1614462

Encountered the same bug today. Resorted to killing the madm process.
```
pstree of apt at the time:
dpkg───initramfs-tools───update-initramf───mkinitramfs───mdadm───mkconf───mdadm
```
```
 sudo dpkg --configure -a
Setting up initramfs-tools (0.122ubuntu8.13) ...
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.122ubuntu8.13) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-138-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.
Terminated
W: mdadm: failed to auto-generate temporary mdadm.conf file.
```