Description of problem:
Add a role to the service accounts using -z/--serviceaccount as argument,and then remove them using -z/--serviceaccount as argument,or remove them using "oc policy remove-role-from-user admin system:serviceaccount:wsuntest:default",the service account could not be removed.



Version-Release number of selected component (if applicable):
# oc version 
oc v1.0.7-287-g60781e3
kubernetes v1.2.0-alpha.1-1107-g4c8e6f4
devnenv_rhel7-2638

How reproducible:
Always

Steps to Reproduce:
1.Check who is admin 
# oc get rolebinding/admins -n wsuntest
2.Add the serviceaccounts to the role
# oc policy add-role-to-user admin -z=defalut --serviceaccount=three -n wsuntest
3.Check if the service accounts are added to admin role
# oc get rolebinding/admins -n wsuntest
4.Remove the serviceaccounts from the role with -z/--serviceaccount
# oc policy remove-role-from-user admin -z=default --serviceaccount=three -n wsuntest
5.Check if the service accounts are removed from admin role
# oc get rolebinding/admins -n wsuntest
6.Remove the serviceaccounts from the role whithout -z/--serviceaccount
oc policy remove-role-from-user admin system:serviceaccount:wsuntest:default -n wsuntest
7.Check if the service accounts are removed from admin role
#  oc get rolebinding/admins -n wsuntest
8.Add the serviceaccounts to the role,but don't use -z
# oc policy add-role-to-user admin system:serviceaccount:wsuntest:one -n wsuntest
9.Check if the service accounts are removed from admin role
#  oc get rolebinding/admins -n wsuntest
10.Remove the serviceaccounts from the role
# oc policy remove-role-from-user admin system:serviceaccount:wsuntest:one -n wsuntest
11.Check if the service accounts are removed from admin role

Actual results:
1.# oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS   SUBJECTS
admins    /admin    system:admin   

3.# oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS   SUBJECTS
admins    /admin    system:admin             defalut, three     

5# oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS   SUBJECTS
admins    /admin    system:admin             defalut, three 

7.#  oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS   SUBJECTS
admins    /admin    system:admin             defalut, three     

9.#  oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS      SUBJECTS
admins    /admin    system:admin             defalut, three, one  

11.The service account "one" is removed
#  oc get rolebinding/admins -n wsuntest
NAME      ROLE      USERS          GROUPS    SERVICE ACCOUNTS   SUBJECTS
admins    /admin    system:admin             defalut, three

Expected results:
5.7 Could remove "default" and "three" service accounts

Additional info: