Clean up in test_server_diagnostics unit test case

This patch changes V3 router to V21 router,
and HTTPRequestV3 to HTTPRequest. which can be shared between
V21 and V2

Partially implements blueprint v2-on-v3-api
Change-Id: Id3c91c377b9ba98c5cf2d1d2b4f476cec3159792
Use HTTPRequest instead of HTTPRequestV3 for v2/v2.1 tests

This patch replace HTTPRequestV3 with HTTPRequest for
test_shelve unit test case, which can be shared between
v2 and v21

Partially implements blueprint v2-on-v3-api
Change-Id: I732335e1f4885a067e42c48c75417ba0b4aba192
move the integrated tests into the functional tree

This moves the integrated tests into the functional tree as an initial
seed for the functional tests. It was agreed to as an early step at
the design summit. Work on cleaning these up will happen after the
move.

PYTHON_HASH_SEED=0 is needed because these tests apparently remain
order dependent.

Also remove the use of test.ReplaceModule, which is an untested
mocking system in the nova tree that doesn't seem to reliably
work. Use stubs instead for the time being, as this will ensure
repeatability of the code.

Part of bp:functional-tests-for-nova

Change-Id: I742c487dd7bca9de3e811c545de477367fff112c
Merge "move the integrated tests into the functional tree"
Merge "Clean up in test_server_diagnostics unit test case"
Merge "Use HTTPRequest instead of HTTPRequestV3 for v2/v2.1 tests"