Change value of SECRET_KEY

Currently SECRET_KEY points to
{ install_lib_dir }}/openstack_dashboard/local/.secret_key_store
however this directory is not writable by www-data:www-data and
attempting to load horizon results in a LockFailed exception being
raised.  Rather than making
{ install_lib_dir }}/openstack_dashboard/local/ writable by
www-data:www-data, we create /var/lib/horizon and point SECRET_KEY to
/var/lib/horizon/.secret_key_stone.

(cherry picked from commit 75b4bbf4fc0be60f22972422f2234836618a12cb)

Conflicts:
	rpc_deployment/inventory/group_vars/horizon.yml
Updates glance client version to fix juno

This update changes the glance client sha to a version that will
allow for the internal URL to be used which was broken in version
0.14.1/2.
Add tempest users to heat_stack_owner role

Any user creating heat stacks needs to be added to this role.  Doing
this resolves some of the failing orchestration tempest tests.

(cherry picked from commit 13dfb3834188e9ed6017e89c6be1c59f1487d493)
Merge pull request #496 from sigmavirus24/backport/366

Backport to proposed/juno - Change value of SECRET_KEY
Merge pull request #515 from mattt416/proposed/juno_346

Add tempest users to heat_stack_owner role
Create alarms for discovered devices

Currently, we create checks for {sda,sdb,sdc}, but not every server will
have these devices.  This commit loops over {{ ansible_devices }}
instead so we create an alarm for any discovered device.

Additionally, if a user variable called maas_excluded_devices exists,
we'll skip over those devices when creating alarms.

(cherry picked from commit 787599a1d05a2d421a5aa93e285988e88b59919f)
Merge pull request #534 from mattt416/juno_430

Create alarms for discovered devices
Run glance-manage as {{ system_user }}

Currently this task is run as root, however as glance has no separate
glance-manage.log file, this _could_ result in
/var/log/glance/glance-api.log being owned by root.  This change causes
glance-manage to be run as {{ system_user }} which should eliminate
this from happening.

(cherry picked from commit 17ae7f3b0976e8fe19aade8725021e468b3616d0)
Ensure OpenStack commands are run as correct user

Currently, a number of OpenStack commands are run as root (namely,
those management related commands to handle db creation/migrations).
This change updates these affected tasks to use sudo to run the commands
as the correct user.

We also make a few other minor changes, namely:

- updating some hard-coded users to reflect {{ system_user }} instead
- removing nova_compute_sshkey_create role from nova-compute.yml
  playbook (this role is already listed in nova-compute-keys.yml, which
  is included in nova-all.yml)
- adding a vars_files to nova-compute-keys.yml so we can reference
  {{ system_user }} instead of the hard-coded nova user
- updating the 'Create the nova SSH key if it doesnt exist' task to use
  sudo rather than su

(cherry picked from commit a4431dfba6094cf232ca866953249156022f7d4a)
Merge pull request #538 from mattt416/juno_507

Ensure OpenStack commands are run as correct user
Merge pull request #537 from mattt416/juno_497

Run glance-manage as {{ system_user }}
Merge pull request #509 from cloudnull/glanceclient-patch-proposed/juno

BACKPORT - Updates glance client version to fix juno