Add support for images context semantic validation

This patch adds support for images context semantic validation, it's one
of the series patches for the bp:
https://blueprints.launchpad.net/rally/+spec/benchmark-context-semantic-validation.
It just lists images to check whether the image service is available.

Partially Implements: blueprint benchmark-context-semantic-validation

Change-Id: Iecd54dc96110e5ce592478601f3c601e4275768d
Added Sahara client

The client is required for further Sahara benchmarking.

Change-Id: Icea34148f6e505a8a8765151324c566f773f6f4e
Update Tempest Config Generator

Updated method func inside generator method
to remove self

Change-Id: I26db0295d6c1ded6c2443e390f3b9c184c6619b9
Closes-Bug:#1343294
Merge "Added Sahara client"
fixes TypeError coercing of tempfile in subunit2json.py

Closes-Bug: #1343312
Change-Id: I9d86169de7dd69311fcf1478f0708a66834d5857
Remove use of random uuid from unit tests

Closes-Bug: #1340015
Change-Id: I07eb638fc2e11c136cbd124538a5dd7ea6120978
Merge "Add support for images context semantic validation"
Reduce number of points in generated charts

In some cases number of iterations is too much for direct charting.

Also reduce number of digits after the decimal point.

Change-Id: I7ae526ae41500a8a0c33a7014e93cde210687df9
Merge "Remove use of random uuid from unit tests"
Added cleanup for sahara objects

This change is required befor adding any sahara benchmarks.

Change-Id: I5f35cb17cfbacdee80afc7e5c153e6acea6451bb
Fix cleaning up neutron resources

Only call remove_interface_router when the port is of type
network:router_interface and use API filtering by tenant_id
to speed up cleanup.

Change-Id: I120cbdf284a759085d77d89d8caac2656a5ca9e4
Closes-Bug: #1346885
Set any_order to True in some unit tests

In some tested methods iteritems() is used, and order of returned items
may be different (belongs on PYTHONHASHSEED).

Change-Id: I66193b530e6f5b986f351ccba6f1a40e6d3ef5f1
Merge "Added cleanup for sahara objects"
Merge "Set any_order to True in some unit tests"
Updated from global requirements

Change-Id: I79c3b759e1676d853454e00b305ffedbdc6cbe4d
Updated rally gate scenarios

Change-Id: I021e4be45cf3e9d92c9e099cec63ae844831c995
Refactored test_images.py and images.py

Refactored test_images.py to include separate tests for each
Method in the Context Class

Also removed default values of arguments to image context class in
images.py which are now mandatory

Change-Id: Iaa510ea10b6f54eb0968382e8ea648fe4dcc288d
Updated _boot_server() to handle floating ip/external networks

The previous code would make use of the external network causing
the test to fail

Closes-Bug: #1347653

Change-Id: I234ae077b6fa9adf5fc64f7c189090d80f904110
Merge "Updated rally gate scenarios"
Merge "Refactored test_images.py and images.py"