missing 'before_end_date' value in lease response

Description:

In lease-create and lease-show APIs response you get values of 'start_date'
and 'end_date' of lease, but missing 'before_end_date' value. It is use full
information if user wants to update 'before_end_date' of lease.

Steps:
1. create a lease
$ blazar lease-create --reservation resource_type=virtual:instance,vcpus=1,memory_mb=1024,disk_gb=20,amount=1,affinity=False --start-date "2018-10-11 12:55" --end-date "2018-10-11 15:55" lease-1

2. Check lease response
Created a new lease:
+--------------+-----------------------------------------------------------------+
| Field | Value |
+--------------+-----------------------------------------------------------------+
| created_at | 2018-10-11 12:05:33 |
| degraded | False |
| end_date | 2018-10-11T15:55:00.000000 |
| events | { |
| | "status": "UNDONE", |
| | "lease_id": "b1f7b2e6-3c0e-4b6b-b2f5-8836eb3996d8", |
| | "event_type": "end_lease", |
| | "created_at": "2018-10-11 12:05:35", |
| | "updated_at": null, |
| | "time": "2018-10-11T15:55:00.000000", |
| | "id": "22ae5220-d008-4fd8-8773-193d4246203f" |
| | } |
| | { |
| | "status": "UNDONE", |
| | "lease_id": "b1f7b2e6-3c0e-4b6b-b2f5-8836eb3996d8", |
| | "event_type": "start_lease", |
| | "created_at": "2018-10-11 12:05:35", |
| | "updated_at": null, |
| | "time": "2018-10-11T12:55:00.000000", |
| | "id": "276bd15d-1f41-436e-b77b-b6762cb5ccc0" |
| | } |
| | { |
| | "status": "UNDONE", |
| | "lease_id": "b1f7b2e6-3c0e-4b6b-b2f5-8836eb3996d8", |
| | "event_type": "before_end_lease", |
| | "created_at": "2018-10-11 12:05:35", |
| | "updated_at": null, |
| | "time": "2018-10-11T14:55:00.000000", |
| | "id": "82e9132b-228e-4fc8-a01b-28d340abf228" |
| | } |
| id | b1f7b2e6-3c0e-4b6b-b2f5-8836eb3996d8 |
| name | lease-1 |
| project_id | bb11c600151245089ac22ce211d76f50 |
| reservations | { |
| | "status": "pending", |
| | "memory_mb": 1024, |
| | "lease_id": "b1f7b2e6-3c0e-4b6b-b2f5-8836eb3996d8", |
| | "resource_properties": "", |
| | "disk_gb": 20, |
| | "resource_id": "00a3ccba-d231-4e31-aacc-ee9e65a92c44", |
| | "created_at": "2018-10-11 12:05:33", |
| | "updated_at": "2018-10-11 12:05:35", |
| | "missing_resources": false, |
| | "server_group_id": "e7f43c55-f669-4a7f-aefc-16fba54a6655", |
| | "amount": 1, |
| | "affinity": false, |
| | "flavor_id": "3b730291-48e2-4828-9875-af80f382eb60", |
| | "id": "3b730291-48e2-4828-9875-af80f382eb60", |
| | "aggregate_id": 106, |
| | "vcpus": 1, |
| | "resource_type": "virtual:instance", |
| | "resources_changed": false |
| | } |
| start_date | 2018-10-11T12:55:00.000000 |
| status | PENDING |
| trust_id | f3f0a175d2ec4d9b854806fd9571d793 |
| updated_at | 2018-10-11 12:05:35 |
| user_id | 9e1363ac34754d9697419c0fbfafe880 |
+--------------+-----------------------------------------------------------------+