cyclades: Fix typo
deploy: Remove contrib and non-free components

Remove 'contrib' and 'non-free' components from debian sources list.
deploy: Make snf-image work with qemu-kvm 2.1.0

Apply workaround to make snf-image work with qemu-kvm 2.1.0 from
wheezy-backports.
stats: Fix race condition where there are no NICs

When a VM doesn't have any NICS attached to it, stats will raise a '500
Internal Server Error'. Fix that by raising an 'ItemNotFound' exception.
cyclades: Fix bug in DB migration

Fix bug in migration 0102 which saves in the 'subnet_ids' column of the
network object the IDs of all subnets that are associated with this
network. A typo in this migration resulted in the 'subnet_ids' field to
contain the id of the network. Also, provide a DB migration to fix this
issue for those that have already installed 0.16rc1.