Fix remove callback user privilege access to login

Callback privilege user must not be allowed to login,similar to IPMI.
This user is used for callback purpose from IPMI point of it, and
must be maintained in bmcweb to be consistent with IPMI, Hence
removing the access to login for callback user

Tested:
1.Create a user with username 'test1' and privilege -
  "Callback" via Redfish.
2.Using that Callback level credentials, try to do
  "Get" at this URI https://<ip-addr>/redfish/v1/Systems/system
3.output: Forbidden
4.use same URL to login from webUI with callback privilege
  https://<ip-addr>/redfish/v1/Systems/system
5.output: Forbidden
Signed-off-by: anil kumar appana <anil.kumarx.appana@intel.com>
Change-Id: I86dac565fc874e5d0fe033640ffc3de576a1f693

1 files changed, 1 insertions, 1 deletions

diff --git a/redfish-core/lib/roles.hpp b/redfish-core/lib/roles.hpp
index fbe8653f77..956f566485 100644
--- a/redfish-core/lib/roles.hpp
+++ b/redfish-core/lib/roles.hpp
@@ -61,7 +61,7 @@ inline bool getAssignedPrivFromRole(std::string_view role,
     }
     else if (role == "Callback")
     {
-        privArray = {"Login"};
+        privArray = {};
     }
     else
     {