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/lib/openbmc_ffdc_list.py b/lib/openbmc_ffdc_list.py
index cd7dd3f..5820532 100755
--- a/lib/openbmc_ffdc_list.py
+++ b/lib/openbmc_ffdc_list.py
@@ -236,9 +236,23 @@
         del FFDC_GET_REQUEST[key]
 
 REDFISH_BASE = "/redfish/v1/"
-REDFISH_ELOG = REDFISH_BASE + "Systems/system/LogServices/EventLog/Entries"
 REDFISH_FIRMWARE = REDFISH_BASE + "UpdateService/FirmwareInventory"
 
+try:
+    REDFISH_SYSTEM_ID = REDFISH_SYSTEM_ID = os.environ.get(
+        "SYSTEM_ID", ""
+    ) or BuiltIn().get_variable_value("${SYSTEM_ID}", default="system")
+
+    REDFISH_ELOG = (
+        REDFISH_BASE
+        + "Systems/"
+        + REDFISH_SYSTEM_ID
+        + "/LogServices/EventLog/Entries"
+    )
+except RobotNotRunningError:
+    REDFISH_ELOG = REDFISH_BASE + "Systems/system/LogServices/EventLog/Entries"
+    pass
+
 # Add file name and corresponding Get Request
 FFDC_GET_REDFISH_REQUEST = {
     "GET REQUESTS": {