Added fix in testcase for cert installation with redfishtool

Changes:
       -  Removed wrong argument passing to library method 'Redfishtool Post'

Tested:
       - Ran the testcase 'Install Server Certificate Using Redfishtool And Verify Via OpenSSL'
         from sandbox successfully.

Change-Id: Id3eee4bf59dff41ce4efd8cbc82c3a7536023473
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 18a2265..c566d9b 100644
--- a/redfish/dmtf_tools/test_redfishtool_certificate.robot
+++ b/redfish/dmtf_tools/test_redfishtool_certificate.robot
@@ -148,7 +148,6 @@
 
     ${response}=  Redfishtool Post
     ...  ${payload}  /redfish/v1/CertificateService/Actions/CertificateService.ReplaceCertificate
-    ...  valid_status_codes=${HTTP_OK}, ${HTTP_NO_CONTENT}
 
     Wait Until Keyword Succeeds  2 mins  15 secs  Verify Certificate Visible Via OpenSSL  ${cert_file_path}