Fail run if nova user is already present with no homedir.
Add one-off playbook to give nova user a homedir.
Configure passwordless-SSH among compute nodes.

This is required for instance resize and migration.
Add support for defining /etc/network/interfaces.d files in host_vars
Merge remote-tracking branch 'upstream/master' into interfaces.d
testenv: bumping test instance boot delay
testenv: use nested KVM rather than QEMU
Merge remote-tracking branch 'upstream/master' into interfaces.d
Move verify-ssh to ~nova/bin/
Merge pull request #398 from blueboxgroup/testenv-use-kvm

testenv: use nested KVM rather than QEMU
Merge pull request #397 from blueboxgroup/interfaces.d

Add support for defining /etc/network/interfaces.d files in host_vars
Merge pull request #389 from blueboxgroup/migrate

Setup ssh keys for nova migrations
Create ~nova/bin
download latest Sensu gem
Configure nova-scheduler to use CoreFilter.

Without this setting, `cpu_allocation_ratio` has no effect,
allowing compute nodes to be over-subscribed.
Alert if any (nova,cinder,neutron) services are down.
Merge remote-tracking branch 'upstream/nova-core-filter' into combine-399-400-401
Merge remote-tracking branch 'upstream/check-os-services' into combine-399-400-401
testenv: use sensu 0.12.5-1
Merge remote-tracking branch 'upstream/release' into combine-399-400-401