Remaining trust uses are consumed even when create token fails

I think we should consume trust use only when getting token sucuess. But, currently if I get token fail the trust use will also be consumed. For example:
curl -i -H "Content-Type:application/json" http://127.0.0.1:35357/v3/auth/tokens -d '{"auth":{"identity":{"methods":["password"], "password":{"user":{"id":"b89cd1d1608f4e6ea588b1338f2621bd","password":"admin"}}},"scope":{"OS-TRUST:trust":{"id":"bcbddcc479304a8a8c39df24a87cce85"}}}}'

If the user(b89cd1d1608f4e6ea588b1338f2621bd) is not the trustee user of the trust(bcbddcc479304a8a8c39df24a87cce85), get token will fail:
{"error": {"message": "User is not a trustee. (Disable debug mode to suppress these details.)", "code": 403, "title": "Forbidden"}}

But, the remaining uses of the trust will be consumed.

This is because we call "trust_api.consume_use" before "token_provider_api.issue_v3_token":https://github.com/openstack/keystone/blob/master/keystone/auth/controllers.py#L375, and issue_v3_token may be fail for some reasons.