Fix testcase to verify replace certificate error

Changes: - Corrected expected error code in keyword
           'Verify Redfishtool Replace Certificate'

Tested: - Ran the testcases for replacing certificate with
          error from sandbox successfully.

Change-Id: Ie93d9a59bcc100bf03af123f7e60f2ac5762df5a
Signed-off-by: manashsarma <manashsarma@in.ibm.com>
diff --git a/redfish/dmtf_tools/test_redfishtool_certificate.robot b/redfish/dmtf_tools/test_redfishtool_certificate.robot
index c566d9b..e006f22 100644
--- a/redfish/dmtf_tools/test_redfishtool_certificate.robot
+++ b/redfish/dmtf_tools/test_redfishtool_certificate.robot
@@ -400,7 +400,7 @@
 
     ${expected_resp}=  Set Variable If
     ...  '${expected_status}' == 'ok'     ${HTTP_OK}, ${HTTP_NO_CONTENT}
-    ...  '${expected_status}' == 'error'  ${HTTP_BAD_REQUEST}
+    ...  '${expected_status}' == 'error'  ${HTTP_NOT_FOUND},${HTTP_INTERNAL_SERVER_ERROR} 
 
     ${response}=  Redfishtool Post
     ...  ${payload}  /redfish/v1/CertificateService/Actions/CertificateService.ReplaceCertificate