Added test_user_update_own_password tests for Identity v2, v3

Added test_user_update_own_password tests for Identity v2, v3
that test non admin user capability to change own password via
public identity client.
Tests check that after updating password token is revoked and
new token is valid; old password is invalid and new one is valid.

Change-Id: I4108312e01bbcacaa9ac6d6b9960ca0e75533f33
3 files changed