Fix test and tag name mismatch

Changes:
     --- ./redfish/managers/test_managers_bmc.robot:
    Test case: Verify Managers Collection Unsupported Methods
    Tag name : Verify_Manager_Collection_Unsupported_Methods

    fixed the Manager string mismatch

Tested:
     -NA
Change-Id: Ie035bc4a0eef5bc6ebda2ec9eadc91c30e542b63
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/managers/test_managers_bmc.robot b/redfish/managers/test_managers_bmc.robot
index aed350e..a829ac9 100644
--- a/redfish/managers/test_managers_bmc.robot
+++ b/redfish/managers/test_managers_bmc.robot
@@ -187,7 +187,7 @@
 
 Verify Managers Collection Unsupported Methods
     [Documentation]  Verify Managers Collection with Unsupported methods.
-    [Tags]  Verify_Manager_Collection_Unsupported_Methods
+    [Tags]  Verify_Managers_Collection_Unsupported_Methods
 
     # Put operation on Managers Collection
     Redfish.Put  /redfish/v1/Managers