Change v3 os-user-data extension to v2.1

This patch changes v3 os-user-data extension to v2.1 and makes v2 unit
tests share between v2 and v2.1.

The differences between v2 and v3 are described on the wiki page
https://wiki.openstack.org/wiki/NovaAPIv2tov3 .

Partially implements blueprint v2-on-v3-api

Change-Id: Ia45398c2ec7ff40851f94260dc10c53766581ff4
Update instance state after compute service died for rebuilded instance

When nova-compute died unexpectedly or rpc message lost unexpectly
and an rebuild operation is ongoing, the instance will be in REBUILD
state forever after the nova-compute service restarts.
Only if admin take actions such as reset its state.
Like what we did for build instance (general spawn)
operation, the instance might not be used so it need to be set to ERROR
state after compute service restarts.

Change-Id: I37748edb3ca0501b6f2fb41fbd75b7b8aa00d59c
Closes-Bug: #1304184
Use default quota values in test_quotas

There are much copy&paste code in test_quotas of v2 API.
This patch adds default quota values and makes use it for each API test
for the readability.

Change-Id: Ib40a1820ea0db93daf231b3384f203ab0ef696ba
Merge "Update instance state after compute service died for rebuilded instance"
Merge "Change v3 os-user-data extension to v2.1"
Merge "Use default quota values in test_quotas"