Add some test_cases for glance_cli

Add some omitted test_cases for glance in tempest

 + test_glance_member_list
 + test_glance_version
 + test_glance_debug_list
 + test_glance_timeout

Change-Id: I5be4abc92f6fe2d3b969e8fb28be128b9f34485b
Adds test to cover Swift healthcheck middleware

Simple middleware, simple test. One test is run:
A single GET is sent to "/healthcheck", a HTTP 200 response is
expected.

Change-Id: If6428259c5094c0b56b57ab0064d017d4c4340f7
Adds api test to test_images

This adds a testcase to test api's
get image by id
get image file
also adds necessary client method for image client.

There was a confussion in the V2 imageclient function
get_image_metadata which has been renamed to get_image
to unify naming convention with V1. So there was change
made in test_images_tags.

Change-Id: Ie96135973b5796652e28aed2e3a09c17cfd26229
Merge "Adds test to cover Swift healthcheck middleware"
Merge "Add some test_cases for glance_cli"
Merge "Adds api test to test_images"