Change the roles paramters

[freesky-edward]

What this PR does / why we need it:
Change the Role list interface as the actual format.
Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Release note:

[coveralls]

Pull Request Test Coverage Report for Build 344

• 1 of 27 (3.7%) changed or added relevant lines in 2 files are covered.
• 25 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.3%) to 68.408%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
openstack/identity/v3/roles/urls.go	0	2	0.0%
openstack/identity/v3/roles/requests.go	1	25	4.0%

Files with Coverage Reduction	New Missed Lines	%
openstack/identity/v3/roles/urls.go	1	85.71%
openstack/identity/v3/roles/requests.go	4	64.9%
openstack/identity/v3/roles/results.go	20	65.79%

Totals
Change from base Build 342:	-0.3%
Covered Lines:	11721
Relevant Lines:	17134

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 344

• 1 of 27 (3.7%) changed or added relevant lines in 2 files are covered.
• 25 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.3%) to 68.408%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
openstack/identity/v3/roles/urls.go	0	2	0.0%
openstack/identity/v3/roles/requests.go	1	25	4.0%

Files with Coverage Reduction	New Missed Lines	%
openstack/identity/v3/roles/urls.go	1	85.71%
openstack/identity/v3/roles/requests.go	4	64.9%
openstack/identity/v3/roles/results.go	20	65.79%

Totals
Change from base Build 342:	-0.3%
Covered Lines:	11721
Relevant Lines:	17134

---

💛 - Coveralls