[rally] Get keystone auth endpoint as request_url
[rally] Get keystone auth endpoint as request_url

JIRA: FUNCTEST-685
Change-Id: Id0d0bcf55451832d9aeb22c3e6b9c21aea4e0911
Signed-off-by: Michael Polenchuk <4b6930fcb8f5524c11625bc5d0e487ba6a54a663@mirantis.com>

mywulin/functest,opnfv/functest,mywulin/functest,opnfv/functest