Guard against content being None

`content` can be passed in as None, so we need to set it to the empty
list if that occurs.

This also fixes the bad-practice of using a mutable data-type as a
default argument.

Fixes bug 1163598

Change-Id: Ie991c9452a21cfb036d3955a094ec345805d63d1
After migrate, catch and remove deleted instances

On the host init, starting with a deleted instance which has been
previously evacuated from the host results in an InstanceNotFound
exception. Catch and log this, and then call driver.destroy() so
that the hypervisor driver can clean up the deleted instance.

If we don't do this during host init, it will cause problems during
periodic tasks.

Fixes bug 1155152

Co-authored-by: Devananda van der Veen <devananda.vdv@gmail.com>

Change-Id: I979a698b8e739b9335f37b81e789285f91977a8e
Fix legacy_net_info guard

The existing code assumes that `legacy_net_info` is always in legacy
mode, meaning a list of tuples which causes it to break when passed a
new-style NetworkInfo object.

Fixes bug 1164152

Change-Id: I2131d9b24045cd7531454b65d97776b11ec3ab02
Imported Translations from Transifex

Change-Id: I2abbf4025e7467a090efba9d1f7820a1fcac29d1
Merge "Guard against content being None"
Merge "Imported Translations from Transifex"
Merge "After migrate, catch and remove deleted instances"
Merge "Fix legacy_net_info guard"