add some negative tests for flavor

add some negative tests for flavor API. and seperate negative testcases
into a dedicated file according to
http://docs.openstack.org/developer/tempest/HACKING.html#negative-tests
and this
bp:https://blueprints.launchpad.net/tempest/+spec/negative-test-files

Change-Id: Ib521c717bfacf98cb092068522d8da36fb79e7c0
add some tests for aggregates

Mainly add some negative tests for Aggregates API, and seperate negative
testcases into a dedicated file according to
http://docs.openstack.org/developer/tempest/HACKING.html#negative-tests.

Change-Id: I7506a5c06218c8f66b2a406138ff1360cc340ca7
Merge "add some tests for aggregates"
Merge "add some negative tests for flavor"