Modify library method  and testcase for DMTF usercase

There two objectives with this change:
1.Test case executed python command file
'Redfish-Usecase-Checkers/account_management/account_management.py';
 with unrecognized arguments. This is corrected.
2.When any use case/test case (inside the python command file 'account_management.py')
 fails, just failure message comes without any information on failed test cases.
 This is fixed now.

Change-Id: Ic99dc5b7a20af631d6459025029b6db5dea305bb
Signed-off-by: Manash Sarma <manashsarma@in.ibm.com>
diff --git a/lib/dmtf_tools_utils.robot b/lib/dmtf_tools_utils.robot
index 5b175ff..1fb538f 100644
--- a/lib/dmtf_tools_utils.robot
+++ b/lib/dmtf_tools_utils.robot
@@ -27,13 +27,14 @@
 
 Run DMTF Tool
     [Documentation]  Execution of the command.
-    [Arguments]      ${rsv_dir_path}  ${command_string}
+    [Arguments]      ${rsv_dir_path}  ${command_string}  ${check_error}=0
 
     # Description of arguments:
     # rsv_dir_path    Directory path for rsv tool (e.g. "Redfish-Service-Validator").
     # command_string  The complete rsv command string to be run.
+    # check_error     It decides if error information is to be checked.
 
-    ${rc}  ${output}=  Shell Cmd  ${command_string}
+    ${rc}  ${output}=  Shell Cmd  ${command_string}  ignore_err=${check_error}
     Log  ${output}
     [Return]  ${output}