Show credentials

This api offers the interface to show credentials.
The credentials dict will be returned.
---
tags:
  - Creds
definitions:
  Credentials:
    type: object
    properties:
      creds_name:
          $ref: '#/definitions/Name'
  Name:
    type: dict
responses:
  200:
    description: Show credentials
    schema:
      $ref: '#/definitions/Credentials'
    examples:
      "OS_AUTH_URL": "https://192.16.1.222:5000/v3"
      "OS_AUTH_VERSION": "3"
      "OS_CACERT": "/home/opnfv/functest/conf/os_cacert"
      "OS_ENDPOINT_TYPE": "publicURL"
      "OS_IDENTITY_API_VERSION": "3"
      "OS_INTERFACE": "publicURL"
      "OS_NO_CACHE": "1"
      "OS_PASSWORD": "990232e0885da343ac805528522d"
      "OS_PROJECT_DOMAIN_NAME": "Default"
      "OS_PROJECT_NAME": "admin"
      "OS_REGION_NAME": "RegionOne"
      "OS_TENANT_NAME": "admin"
      "OS_USERNAME": "admin"
      "OS_USER_DOMAIN_NAME": "Default"