add some tests for host and seperate negative ones

For host operation, there are some APIs: list, show, update, startup,
shutdown, reboot. This patch will mainly add some negative tests for
update, startup, shutdown, reboot. It is important to note that, for
Libvirt Driver currently, there are no implementations for
set_host_enabled/host_maintenance_mode/host_power_action.

Change-Id: Ia810b956a20eae67e8ec43e3edf9fcb019f71711
Add filenames to skip_tracker.py output

This commit adds support for also printing the filenames along with
the bug number in the skip tracker output. This should make it
slightly easier to find the skips and remove them.

Change-Id: Ia3502f1a48bb9e028d046fa60307e398582e6124
add tests for set_metadata in aggregate

Change-Id: I1aae38be9780e4f8c9e6bf595837c71f510fafce
Added some test for image tags

Image-tags are introduced in v2 api
of glance.one can create and delete a
tag for image.

Change-Id: I2ef7e085eb2577232dc0ef08d139341978b007f1
Merge "add some tests for host and seperate negative ones"
Merge "Added some test for image tags"
Merge "add tests for set_metadata in aggregate"
Merge "Add filenames to skip_tracker.py output"