Set system, chassis, and bmc as global variables

Changes:
  - Add SYSTEM_ID as a global variable and set to default value system
  - Replace redfish/v1/Systems/system to redfish/v1/Systems/SYSTEM_ID
  - Replace redfish/v1/Chassis/chassis to redfish/v1/Chassis/CHASSIS_ID
  - Replace redfish/v1/Managers/bmc to redfish/v1/Managers/MANAGER_ID

Tested:
  - Tested on sandbox with the changes with sample test run with
    sample test ID runs
    1. without SYSTEM_ID provided
    2. with -v SYSTEM_ID:system1
    3. with export SYSTEM_ID=""
    3. with export SYSTEM_ID="system2"

Change-Id: Ifc412b20038cef1eba632caaa6c300be328259bd
Signed-off-by: Wilson Suen <wilsons@supermicro.com>
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/systems/eventlog/test_event_logging.robot b/redfish/systems/eventlog/test_event_logging.robot
index 6c4e22a..42136d3 100644
--- a/redfish/systems/eventlog/test_event_logging.robot
+++ b/redfish/systems/eventlog/test_event_logging.robot
@@ -66,7 +66,7 @@
     Create Test PEL Log
     ${elog_entry}=  Get Event Logs
 
-    Redfish.Delete  /redfish/v1/Systems/system/LogServices/EventLog/Entries/${elog_entry[0]["Id"]}
+    Redfish.Delete  /redfish/v1/Systems/${SYSTEM_ID}/LogServices/EventLog/Entries/${elog_entry[0]["Id"]}
 
     ${error_entries}=  Get Redfish Error Entries
     Should Be Empty  ${error_entries}
@@ -338,7 +338,7 @@
     Create Test PEL Log
     Create Test PEL Log
     ${error_entries_before}=  Get Redfish Error Entries
-    Redfish.Delete  /redfish/v1/Systems/system/LogServices/EventLog/Entries/${error_entries_before[0]}
+    Redfish.Delete  /redfish/v1/Systems/${SYSTEM_ID}/LogServices/EventLog/Entries/${error_entries_before[0]}
 
     ${error_entries_after}=  Get Redfish Error Entries
     Should Not Contain  ${error_entries_after}  ${error_entries_before[0]}
@@ -477,7 +477,7 @@
 
 Get Redfish Error Entries
     [Documentation]  Return Redfish error ids list.
-    ${error_uris}=  redfish_utils.get_member_list  /redfish/v1/Systems/system/LogServices/EventLog/Entries
+    ${error_uris}=  redfish_utils.get_member_list  /redfish/v1/Systems/${SYSTEM_ID}/LogServices/EventLog/Entries
     ${error_ids}=  Create List
 
     FOR  ${error_uri}  IN  @{error_uris}