Fix misused assertTrue in unit tests

Refactored unit tests to use assertEqual instead of assertTrue
where needed.

Fixes bug #1226374

Change-Id: Iac5117c7a8dd3769aa6e303c6830aad291d5a0f7
Do not allow the same member to be added twice

This patch add an existence check before add new member for image.

Fixes bug 1231485

Change-Id: I10d37c6f169e070ea6699cca78b6360be9fb11dc
Glance manage should parse glance-api.conf

glance-manage does not currently parse glance-api.conf, when
glance-registry.conf is present. Currently it's parsed conditionally.
But, when some configs from glance-api.conf are required, we would
need parse them both.
eg. CONF.swift_store_user, CONF.swift_store_key in glance-api.conf

Fixes bug #1225863

Change-Id: I553c1bb460229489b38a57d9c91995816bfe09ee
Merge "Fix misused assertTrue in unit tests"
Merge "Do not allow the same member to be added twice"
Merge "Glance manage should parse glance-api.conf"